14: 35-year-old woman with missed period

Question 1

Signs of Pregnancy

Answer 1

Classic signs of pregnancy include a delayed menstrual period, symptoms of nausea, breast tenderness, and malaise. Additional classic signs include a bluish discoloration of the cervix from venous congestion (Chadwick’s sign), usually visible by eight to 10 weeks gestation, and a palpably gravid uterus, usually easily discerned by 10 to 12 weeks gestation.

Question 2

Accurate Pregnancy Dating

Answer 2

Due date
The usual due date is calculated by determining the day 40 weeks after the beginning of the last menstrual period. A simple rule of thumb (Naegle’s Rule) is to subtract three months and add 7 days.
About 5% of babies are born on their due date, with most deliveries occurring within two weeks of the due date (either before or after).

Gestational age

Last menstrual period (LMP)
»During pregnancy, gestational age is also recorded as the time elapsed since the first day of the last menstrual period.
»In a woman with regular periods, using the date of the last menstrual period is usually the most accurate dating method.

Ultrasound
If uncertain, either due to uncertain or unknown last menstrual period (LMP) or potential size/date discrepancies that arise during the pregnancy, an ultrasound can be used to estimate the gestational age of the fetus. When used for dating, ultrasound is most accurate during early pregnancy and should be performed as early as possible (and no later than 20 weeks).

Most clinicians will use dates determined by ultrasound for any discrepancy of:
»more than one week between the ultrasound and another method in the first trimester
»more than two weeks in the second trimester
»more than three weeks third trimester

Fundal height
In the third trimester, ultrasound dating is generally no more accurate than dating by estimated fundal height alone. At 20 weeks, the top of the uterine fundus is usually at the level of the umbilicus, and after 20 weeks, it elevates approximately 1 cm above the umbilicus for each week of pregnancy.

Pregnancy dating
Gestational age is calculated as the time elapsed since the first day of the last menstrual period (LMP). A pregnancy wheel, online gestational age calculator, or the electronic medical record are helpful tools in calculating the gestational age. A note of caution: gestational age is not the same as the embryonic age (also called conceptional or developmental age) of the embryo, which is calculated from the date of fertilization, or about 2 weeks after the first date of the LMP.

Question 3

Obtaining a Complete Prenatal History

Answer 3

Medical history
Medical areas to ask about include any depression or mood disorders and specific conditions that increase risks in pregnancy, such as a personal history of diabetes, hypertension, heart disease, seizures, kidney disease, autoimmune, endocrine, or neurologic disorders. Also, information about specific infections should be elicited, including any sexually transmitted infections (i.e., gonorrhea, Chlamydia, syphilis, warts, herpes), HIV, TB (exposure or disease), and varicella (chicken pox).

Obstetric history
A complete obstetric history should be elicited, including the menstrual history and information about previous pregnancies (number, miscarriages, abortions, delivery method (vaginal or cesarean), infant weight, and any pregnancy or delivery complications). Some medical records will have a separate tab or area to record the obstetric history.

History of genetic risk factors
Include a history of any family members with blood disorders (i.e., thalassemia in persons of Italian, Greek, Mediterranean or Asian descent; sickle cell disease or trait, especially in those of African descent; hemophilia), neural tube defects (meningomyelocele, spina bifida, anencephaly), congenital heart defects, Down’s syndrome, Tay-Sachs disease, cystic fibrosis, mental retardation, metabolic disorders, or other inherited genetic or chromosomal disorders.

Social history
A careful review of the social history should include assessment of specific environmental risk factors as well as relationships. These include smoking, current alcohol or drug use, over-the-counter medications, chemical exposures, pets, occupation, stress, support systems, and other circumstances that may affect a pregnancy.

Question 4

Initial Pregnancy Visit Counseling

Answer 4

Remember that not all patients want to be pregnant, so it’s always good to check in with them to see how they’re feeling about it.

Discuss early pregnancy counseling and perform recommended health maintenance exams.

Ask all pregnant patients about intimate partner violence, as it is more common during pregnancy.

Question 5

Fetal Development - First Trimester

Answer 5

During the first 12 weeks, the heart, spine, arms, legs, and other organs begin to develop. The neural tube closes by 4 weeks. Around 7-8 weeks, the heart will begin to beat and the fetus will begin to move.

Question 6

Workplace conditions

Answer 6

Some working conditions, such as prolonged standing and exposure to certain chemicals, are associated with pregnancy complications.

Question 7

Exercise

Answer 7

Pregnant women should avoid activities that put them at risk for falls or abdominal injuries.

At least 30 minutes of moderate exercise on most days of the week is a reasonable activity level for most pregnant women.

Question 8

Sex

Answer 8

Sexual intercourse during pregnancy is not associated with adverse outcomes.

Question 9

Medications, over- the-counter medications, and herbal remedies

Answer 9

Few medications have been proven safe for use in pregnant women, particularly during the first trimester of pregnancy.

The risks associated with individual medications should be reviewed based on the patient’s needs.

Question 10

Substance use: alcohol

Answer 10

There is no known safe amount of alcohol consumption during pregnancy. Abstinence is recommended.

Question 11

Substance use: illicit drugs

Answer 11

All pregnant women should be informed of the potential adverse effects of drug use on the fetus.

Question 12

Substance use: smoking

Answer 12

All pregnant women should be screened for tobacco use, and pregnancy-tailored counseling should be provided to smokers.

Question 13

Hair treatments

Answer 13

Although hair dyes and treatments have not been associated clearly with fetal malformation, exposure to these treatments should be avoided during early pregnancy.

Question 14

Hot Tubs

Answer 14

Hot tubs and saunas should be avoided during the first trimester of pregnancy.

Maternal heat exposure during pregnancy has been associated with neural tube defects and miscarriage.

Question 15

Nutrition and food safety

Answer 15

Eat a healthy diet with a variety of foods, including protein (meat, dairy), fruits, vegetables, and whole grains.

Avoid raw eggs, unpasteurized milk or milk products, soft cheeses (such as feta, brie, veined, Camembert, and Mexican queso fresco), unwashed fruits or vegetables, raw fish, shellfish, and large, steak-like fish (such as shark, swordfish, king mackerel, and tilefish).

Question 16

Dietary supplements

Answer 16

Daily prenatal vitamin, which provides the recommended folic acid (0.4 to 0.8 mg per day) and iron (30 mg per day) for pregnant women

Question 17

Food Safety During Pregnancy

Answer 17

Caffeine
Likely safe in moderate amounts
Based on observational studies, although high caffeine consumption has been associated with spontaneous abortion and low-birth-weight infants. However, confounding factors such as smoking, alcohol use, nausea, and age cannot be ruled out.

Shark, swordfish, king mackerel, and tilefish
Mercury poisoning
Large ocean fish tend to accumulate mercury in their tissues, and since exposure to high levels of mercury in fish can lead to neurologic abnormalities in women and their infants, the CDC recommends that pregnant women avoid them.

Unwashed fruits and vegetables
Toxplasmosis and listeriosis
Based primarily on case reports.

Unpasteurized milk
Toxplasmosis and listeriosis
Based primarily on case reports.

Raw eggs
Salmonella
Based primarily on case reports.

Soft cheese
Listeriosis
Based primarily on case reports.

Aspartame
Likely safe in moderate amounts
Women with phenylketonuria should avoid aspartame; however, adverse effects from aspartame during pregnancy in women without PKU have not been demonstrated.

Saccharin
Known to cross the placenta, and women should use caution when consuming foods with saccharin.

Question 18

Prenatal Follow-up - 10 Weeks

Answer 18

Normal weight
18.5-24.9
Expect to gain 25-35 lbs

Overweight
25-29.9
Limit weight gain to 15-25 lbs

Obese
>30
Limit weight gain to 11-20 lbs

Blood pressure elevation during pregnancy, or gestational hypertension, can result in potential serious complications for the mother and fetus. Although the optimal frequency for measurement is not known, most guidelines recommend checking the mother’s blood pressure at every visit.

Fetal heart tones are usually first heard by Doppler fetoscope between 10-12 weeks. It would not be unusual to hear a heart beat at a 10 week visit, but also would not be a concern if it was not heard yet. The presence of heart tones indicates a viable fetus and may provide psychological reassurance to the mother, but otherwise has not been shown to have particular clinical or predictive value.

At 10 weeks, the fundus may be just palpable at the pelvic brim. From 20 weeks onward, the fundal height in centimeters often correlates with the weeks of gestation. Measurement of the fundal height is subject to inter- and intra-observerational error, but it is a simple and inexpensive test that can assess appropriate growth of the fetus.

Question 19

Prenatal Vaccinations

Answer 19

Pregnant women are at increased risk for complications from influenza, so the influenza vaccine is recommended for all pregnant women. The intramuscular preparation of the vaccine is an inactivated vaccine and is safe to give at any time during pregnancy. Note: fluMist or other live-attenuated virus preparations are not recommended during pregnancy.

If indicated, it is recommended that routine Rhogam immunization be given at 28 weeks’ gestation and within 72 hours after delivery as well as with any episodes of vaginal or intrauterine bleeding.

Rubella immunization needs to be given to prevent maternal rubella infection during a future pregnancy; however, as a live vaccine, it not safe to give until after completion of a current pregnancy. It is often given in the hospital after delivery and before the mother goes home.

Question 20

Nausea and Vomiting in Pregnancy

Answer 20

Nausea and vomiting in pregnancy is usually self-limited, beginning between the fourth and seventh week and resolving by the 20th week in most women.

About 1 in 200 women develop persistent vomiting, which leads to dehydration, ketosis, electrolyte disturbances, and weight loss, a condition called hyperemesis gravidarum.

Dietary measures:
»Eat frequent, small meals, avoid smells and food textures that cause nausea.
»Solid foods should be bland tasting, high in carbohydrates, and low in fat.
»Salty foods usually can be tolerated early in the morning, and sour and tart liquids often are tolerated better than water.

Question 21

Fetal Development - Second Trimester

Answer 21

At 18 weeks, the baby will able to display facial expressions, have early skeletal development and may display perceptible movements. The baby’s sex can be determined via ultrasound at this point. Soon, the baby will have visible hair, fingerprints and footprints. Over the next several weeks, the baby will continue to grow, and its lungs, liver and immune system will continue to mature.

Question 22

Placenta Previa: Epidemiology, Outcomes, Complications, Management

Answer 22

Placenta previa is uncommon, occurring in 0.3 to 0.5% of pregnancies. It is more common in women who:

• -have had a prior pregnancy
• -are older (>35)
• -smoke
• -have had twins or a higher multiple pregnancy
• -have had previous uterine surgery, including prior cesarean section

Placenta previa is more likely to resolve when detected earlier in pregnancy.
Marginal or incomplete previas are more likely to resolve than complete previas.

Question 23

Placenta previa complications

Answer 23

When the placenta attaches low in the uterus, it can cover the cervical os, which can lead to excessive bleeding at or prior to delivery, jeopardizing the health of the fetus.

While bleeding from placenta previa can occur at any time, bleeding more often occurs later in pregnancy, either late in the second or in the third trimester.

With the advent of ultrasound, it is usually diagnosed before a woman has any bleeding.

Question 24

management of placenta previa

Answer 24

Subsequent ultrasound surveillance is indicated in women who have placenta previa to document progression or resolution.

In the absence of any symptoms, women with previa can be at home; however, they should be counseled about the risk of bleeding and seek prompt attention with any bleeding.

If placenta previa does not resolve, delivery by cesarean is usually required.

Question 25

Chronic hypertension

Answer 25

Blood pressure elevation first detected before the 20th week of pregnancy that persists beyond 12 weeks postpartum.

Women with gestational hypertension cannot be definitively classified until after this period has elapsed.

Question 26

Gestational hypertension

Answer 26

The presence of persistent systolic blood pressure of ≥140 mmHg and/or a diastolic blood pressure of ≥90 mmHg, without proteinuria, in a previously normotensive pregnant woman at or after 20 weeks of gestation.

Tends to recur in subsequent pregnancies and also increases the risk of developing hypertension later in life.

Women who have gestational hypertension may be further characterized depending on subsequent findings, such as the presence of proteinuria (preeclampsia).

Question 27

Preeclampsia

Answer 27

The presence of persistent systolic blood pressure of ≥ 140 mmHg and/or a diastolic blood pressure of ≥ 90 mmHg, with proteinuria of 0.3 grams or greater in a 24-hour urine specimen.

Women who develop gestational hypertension earlier in pregnancy are more likely to develop preeclampsia than those who have their first blood pressure elevation later in pregnancy.

The risk of developing preeclampsia in a woman with elevated blood pressure first measured at < 30 weeks gestation has been estimated at 42%, and when first detected at or after 36 weeks has been estimated at 10%.

Question 28

Eclampsia

Answer 28

Eclampsia describes the occurrence of one or more convulsions in the presence of preeclampsia without the presence of another underlying neurologic disorder in a pregnant woman with a history of elevated blood pressure and proteinuria.

Eclampsia occurs in about 0.5% of women with mild preeclampsia and in about 2-3% of women with severe preeclampsia. The cause of seizures in eclampsia is not known.

Risk factors for preeclampsia and eclampsia are similar. White, nulliparous women from lower socioeconomic backgrounds are at higher risk, and the incidence appears to be higher in younger (teenage and low twenties) and older (> 35 years) women.

Question 29

Screening for Gestational Diabetes

Answer 29

Screening should be performed at 24 to 28 weeks with a one-hour glucose tolerance test.

Question 30

Symptoms of Severe Preeclampsia

Answer 30

Visual disturbances, severe headache, right upper quadrant or epigastric pain, nausea, vomiting, decreased urine output

Question 31

Fetal Development - Week 27

Answer 31

Over the next few weeks, the fetus’ eyes will open and begin to detect light. The fetus will also practice breathing. By 36 weeks, the fetus will gain weight more quickly.

Question 32

Screening for Gestational Diabetes

Answer 32

The three-hour glucose tolerance test is performed by measuring the patient’s glucose after fasting and then one, two, and three hours after ingesting a 100-gram glucose load, usually in the form of a solution that the patient drinks. Two sets of criteria can be used to define an abnormal three-hour glucose tolerance test. The Fourth International Workshop-Conference on Gestational Diabetes defined gestational diabetes as the presence of two or more of the following serum glucose values:
»Fasting serum glucose concentration ≥ 95 mg/dL (5.3 mmol/L)
»One-hour serum glucose concentration ≥ 180 mg/dL (10 mmol/L)
»Two-hour serum glucose concentration ≥ 155 mg/dL (8.6 mmol/L)
»Three-hour serum glucose concentration ≥140 mg/dL (7.8 mmol/L)

These critera are also sometimes referred to as the Carpenter/Coustan criteria.
Another set of criteria is from the National Diabetes Data Group:
»Fasting serum glucose concentration ≥ 105 mg/dL (5.8 mmol/L)
»One-hour serum glucose concentration ≥ 190 mg/dL (10.5 mmol/L)
»Two-hour serum glucose concentration ≥ 165 mg/dL (9.2 mmol/L)
»Three-hour serum glucose concentration ≥145 mg/dL (8.0 mmol/L)

While the use of the Carpenter/Coustan criteria offers improved sensitivity in detecting gestational diabetes, some studies suggest that using the lower cutoff values does not provide significant benefit to mother or fetus and may be associated with increased costs of care. Currently, the American College of Obstetrics and Gynecology considers both criteria acceptable for the diagnosis of gestational diabetes.

Question 33

Screening for gestational diabetes is important because there are many risks associated with it, including:

Answer 33

> preeclampsia
fetal macrosomia (large babies who also may have a disproportionately large trunk to head ratio, increasing risks for shoulder dystocia in labor)
birth trauma
need for operative delivery
neonatal mortality
newborn complications (hypoglycemia, hyperbilirubinemia, hypocalcemia, and others)

Question 34

Assessing Group B Strep Status

Answer 34

Group B strep (GBS) is the most common cause of life-threatening infection in newborns, including sepsis, meningitis, and newborn pneumonia. Premature infants have a higher risk of GBS infection, but most cases occur in full term infants. About half of the cases occur during the first week of life, and most of these cases are preventable by giving intravenous antibiotics to women in labor who are infected with or at high risk for GBS.

Women with GBS bacteriuria during their current pregnancy or who previously gave birth to an infant with early-onset group B strep disease should receive intrapartum antimicrobial prophylaxis. Current (2002) guidelines for GBS screening recommend universal prenatal screening for vaginal and rectal GBS colonization (a culture swab is inserted into the vagina, along the perineum and into the rectum, and then sent to the lab) of all pregnant women at 35-37 weeks’ gestation. It is not standard practice to perform urine screening for GBS. If positive, penicillin is the first line agent for intrapartum antibiotic prophylaxis, with ampicillin an acceptable alternative if penicillin is unavailable.

Question 35

The most common skin eruptions in pregnancy are a related group of itchy rashes that include:

Answer 35

pruritic urticarial papules and plaques of pregnancy (PUPPP)
women develop papulovesicular lesions on the trunk and extremities

prurigo of pregnancy
generally appears as excoriated areas on the trunk or limbs

pruritic folliculitis
rash may be centered around hair follicles and have an associated pustular appearance

Question 36

Features of Down Syndrome

Answer 36

Down syndrome is characterized by a number of physical features, many of which affect the appearance of the head, neck, and extremities. Not all features are present in a given individual, but most infants with this syndrome have between 4 and 6 of the following signs:
Flat facial profile
Poor Moro reflex
Excessive skin at nape of the neck 
Slanted palpebral fissures
Hypotonia
Hyperflexibility of joints
Dysplasia of pelvis
Anomalous ears
Dysplasia of midphalanx of fifth finger Transverse palmar (Simian) crease

The Moro reflex is elicited by moving the head quickly downward from its resting or upright position. In a normal infant, symmetric extension and abduction of the arms as well as opening of the hands is followed by flexion of the upper extremities back across the chest. Infants with Down syndrome often have a less pronounced reflex as well as hypotonia.

Question 37

Postpartum Contraception

Answer 37

Progestin-only pills, injectable progestin (Depo-Provera), and progestin implants (Implanon) can be started immediately post partum. Advantages to these methods include the minimal effect of progestins on blood pressure, coagulation factors or lipid levels, and the lack of increased risk of stroke, myocardial infarction, or venous thromboembolism with progestin-only contraceptives. Potential disadvantages include the need to take a daily pill at the same time every day (for maximum effectiveness) with a progestin-only pill and irregular bleeding, particularly within the first few months.

In women who are breastfeeding, progestins do not appear to cause changes in the composition or volume of breast milk or have any negative effect on the infant. However, due to theoretical concerns about the role of progestins in the initiation and production of breast milk, agencies such as World Health Organization (WHO) and the American College of Obstetricians and Gynecologists (ACOG) recommend that women not begin progestin- only contraception until six weeks if exclusively breastfeeding. In clinical situations where follow-up is uncertain, it may be advisable to initiate contraception before discharge from the hospital.

Copper-containing IUDs are the only type of IUD approved for use postpartum and may be inserted immediately. Immediate insertion has been shown to be safe and effective, although earlier insertion has a slightly higher expulsion rate compare to insertion at 4-6 weeks postpartum. Levonorgestrel-releasing IUDs (Mirena) should not be inserted until 6 weeks post-partum (full involution of the uterus) due to a higher risk of perforation and expulsion.

Use of combined oral contraceptives postpartum and in lactating women is controversial. Women may benefit from reduced coagulation-related risks (such as DVT) by waiting four or more weeks postpartum, and combined oral contraceptives are known to suppress milk production in the early postpartum period. However, clinical trials have shown mixed results with regard to the effect of combined oral contraceptives on milk supply and infant growth, and a Cochrane review concluded that no evidence-based recommendation can be made about the use of combined oral contraceptives in lactating women.

Question 38

Postpartum Blues & Depression

Answer 38

Postpartum blues refers to mild, though often rapid, fluctuations in mood within the first two weeks postpartum, often peaking at about day five. Multiple factors likely contribute to postpartum blues. They usually resolve over time with support, reassurance, and rest. Women with postpartum blues should be counseled about seeking care if symptoms worsen or are not improved by two-weeks postpartum.

Postpartum depression occurs in about 15% of women and refers to the onset of clinical depression (using the same criteria as for those who are non-pregnant) within the first four weeks postpartum. In clinical practice, onset within the first year after delivery of an infant is often referred to as postpartum depression. Multiple risk factors have been associated with postpartum depression. Some of these include stressful life events over the preceding year; unplanned pregnancy; lack of spousal or partner support; personal history of mental disorders; and, especially relevant in this case, having an infant with a congenital malformation.

Question 39

Management of Bacterial Vaginosis During Pregnancy

Answer 39

The appropriate treatment for symptomatic bacterial vaginosis is metronidazole.

Question 40

Studies to Diagnose Pregnancy

Answer 40

Home pregnancy tests are a reliable indication of pregnancy. The sensitivity and specificity of home pregnancy tests may vary between brands and manufacturers; however, most tests are highly sensitive at the time of a missed period in a woman with previously regular periods and may even be positive up to several days prior to a missed period. The FDA threshold for home tests at the time of a missed period is 50 mIU/mL, and most home urine pregnancy tests are positive at concentrations of ≥ 25 mIU/mL. The presence of even a very faint line along with the control strip is considered a positive test. However, since home pregnancy tests are done under a variety of circumstances and without rigorous lab controls, most clinicians will repeat a urine pregnancy test in the office for confirmation.

Blood tests of hCG can detect levels as low as 5 mIU/mL, although care needs to be taken regarding the potential for false positives at this very low level. Blood tests of hCG are not usually used for initial diagnosis, but can be very helpful in determining the viability of a pregnancy since hCG levels rise predictably in early pregnancy. Levels of hCG double approximately every 2.2 days over the first few weeks and then double more slowly approximately every 3.5 days by 9 weeks. Levels of hCG peak at 10-12 weeks and then decline rapidly thereafter until 22 weeks, when levels gradually rise until delivery.

Transvaginal ultrasound (TVUS) is more sensitive than transabdominal ultrasound in detecting early pregnancy. A gestational sac can often be visualized by 4-5 weeks’ gestation, and a fetal pole is often seen by 5-6 weeks. In women who have irregular periods or have other risk factors, such as vaginal bleeding, TVUS can be a useful tool for dating pregnancy as well as evaluating for ectopic (tubal) pregnancy and other abnormalities.

Question 41

blood type/Rh status

Answer 41

ABO and Rh typing are used to assess risk of maternal-fetal transfusion reactions (i.e., hemolytic anemia in the newborn due to the presence of maternal antibodies) should the baby’s blood type be different than the mother’s.

Additionally, anti-Rh antibodies (in the U.S. known as RhoGAM or Rhogam ) can be given to mothers who are Rh negative to prevent sensitization of the maternal immune system to Rh antigens if the baby’s blood type is Rh positive.

Question 42

chlamydia screening

Answer 42

The USPSTF recommends (level B) screening for chlamydia and gonorrhea in sexually active women age 24 years and younger and in older women who are at increased risk for infection.

Age is a strong predictor of risk for chlamydial and gonococcal infections, with the highest infection rates occurring in women aged 20 to 24 years, followed by females aged 15 to 19 years. Chlamydial infections are 10 times more prevalent than gonococcal infections in young adult women

Other risk factors for infection include having a new sex partner, more than 1 sex partner, a sex partner with concurrent partners, or a sex partner who has an STI; inconsistent condom use among persons who are not in mutually monogamous relationships; previous or coexisting STI; and exchanging sex for money or drugs.

Prevalence is also higher among incarcerated populations, military recruits, and patients receiving care at public STI clinics. There are also racial and ethnic differences in STI prevalence. In 2012, black and Hispanic persons had higher rates of infection than white persons. Clinicians should consider the communities they serve and may want to consult local public health authorities for guidance on identifying groups that are at increased risk. Gonococcal infection, in particular, is concentrated in specific geographic locations and communities.

Question 43

HIV test

Answer 43

HIV testing is recommended for all pregnant women. Some areas in the U.S. and Canada may use “opt-out” voluntary testing strategies to improve screening rates.

Universal screening for rubella, syphilis, and hepatitis B surface (not core, as in answer E above) antigen are also recommended. The presence of Hep B surface antigen is an indication of infection with Hep B, and, if present, may warrant further investigation (such as testing for Hep B core antigen, which is a marker of active infection).

Question 44

urinalysis

Answer 44

Routine dipstick urinalysis is often performed at every visit for prenatal patients; however, studies have shown that it does not reliably detect proteinuria (which may indicate gestational hypertension or pre-eclampsia) and that the presence of trace glycosuria (a potential indicator of gestational diabetes) is also unreliable for screening. Some guidelines have encouraged discontinuation of routine dipstick urinalysis, although others retain it as a part of routine prenatal care visits.

Question 45

hep B screening

Answer 45

The U.S. Preventive Services Task Force (USPSTF) recommends screening for hepatitis B virus (HBV) infection in pregnant women at their first prenatal visit (Level A).

Question 46

Hgb/Hematocrit

Answer 46

Anemia screening provides baseline hemoglobin/hematocrit concentrations and directs the need for potential therapy.

Question 47

more tests

Answer 47

Papanicolau test
The first visit also provides an opportunity to complete cervical cancer screening with a Pap test, especially in women who have not been screened recently. All pregnant women should also be screened for asymptomatic bacteriuria with a urine test, but the recommended time would be at a later visit when she is between 12-16 weeks’ gestation.

Hepatitis C antibody screen
Hepatitis C antibody screening should be offered to women with risk factors such as contact with prison inmates, intravenous drug use, HIV-positive, multiple sexual partners, tattoos, or elevated liver enzymes.

Varicella
Women should be asked about a history of chicken pox; women with no history can have serologic testing for varicella zoster IgG. Non-immune women should be offered preconception or postpartum varicella vaccination. Varicella vaccination is contraindicated in pregnancy.

Herpes I/II antibodies
All patients should be asked about a history of genital and orolabial herpes simplex virus infection; women who do not have a history of herpes should be counseled about avoiding exposure during pregnancy. Women with a history of recurrent HSV should be counseled about the use of antiviral medicine (such as acyclovir) to reduce risk of cesarean delivery due to active lesions at the time of delivery (the presence of active lesions during labor is a contraindication for vaginal delivery).

Bacterial vaginosis
Screening for bacterial vaginosis is not recommended; however, symptomatic women should be treated. Screening may be considered in women with risk factors for pre-term delivery.

Ultrasound
Routine ultrasound screening in pregnancy has not been linked to improved perinatal outcomes. Ultrasound can be useful for accurately determining gestational age early on in pregnancy. Most experts agree that pregnant women should be offered routine ultrasound screening for structural anomalies between 18-20 weeks’ gestation.

Other TORCH infections
Universal screening for toxoplasmosis, cytomegalovirus, and parvovirus is not recommended.

Question 48

Screening for Fetal Anamolies

Answer 48

Prenatal maternal (“triple” or “quad”) serum screening consists of measuring three or four chemical markers present in the mother’s blood during pregnancy: alpha-fetoprotein (AFP), human chorionic gonadotropin (hCG), unconjugated estriol, and (only in the quad screen) dimeric inhibin A. Abnormal levels of these serum markers may indicate increased risk for neural tube defects, trisomy 21, and trisomy 18. Serum screening is not usually performed until approximately 15-21 weeks’ gestation.

Some centers may perform ultrasound for fetal nuchal (neck) translucency along with screening for several serum biomarkers (free-hCG, pregnancy-associated protein plasma A) at 10-14 weeks as an additional method for screening for neural tube defects. The advantages of both early detection and slightly improved sensitivity for detecting congenital defects with early biomarker and fetal nuchal translucency testing should be balanced with their cost and availability. Invasive prenatal genetic testing includes chorionic villus sampling in the first trimester and amniocentesis in the second trimester. Many women will choose non- invasive screening tests as a first line to establish their risk.

Routine ultrasound for fetal anomalies is not recommended until 18-20 weeks’ gestation.

Question 49

Quad Screen Sensitivity

Answer 49

When three chemical markers (alpha fetoprotein [AFP], estriol, and hCG) are used, the test is often referred to as a “triple screen”; and when a fourth is added (inhibin-A), the test is referred to as a “quad” screen. The triple screen detects Down syndrome in about 69% of cases, and the quad screen detects Down syndrome in about 81% of cases with a false-positive rate of 5%.

A key benefit of serum screening in pregnancy is the ability to assess the risk of certain birth defects. However, the sensitivity of these tests is not ideal, and false positives and negatives occur. If a serum triple or quad screen is positive, it identifies patients at higher risk but does not rule disease in or out. Subsequent testing is required for further evaluation.

Some women may wish to have knowledge about their fetus in order to make decisions about continuing the pregnancy, and others may wish to complete screening for the ability to find out ahead of time if there are potential issues that may affect later pregnancy or the child once born. Others may decide the tests would not affect their decisions and/or would not be helpful to them, and so they may decline having the initial serum screening test.

Question 50

Risk of Spontaneous Abortion from Amniocentesis

Answer 50

The exact rate of spontaneous abortion attributed to amniocentesis is uncertain. The American College of Obstetricians and Gynecologists (ACOG) cites an amniocentesis-related risk of fetal loss of 1/300 to 1/500.

Question 51

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Placenta previa

Answer 51

Placenta previa is the cause of 22% of cases of third trimester vaginal bleeding.

Occurs when the placenta attaches low in the uterus and covers the cervical os. This can lead to excessive bleeding, jeopardizing the health of the fetus.

Most commonly presents with painless vaginal bleeding after 20 weeks’ gestation.

The bleeding is usually bright red.
Contractions occur in 10-20% of cases, but previa is usually not accompanied by abdominal pain.

Bleeding from previa is often spontaneous.

Patients with (unresolved) placenta previa are usually advised to omit sexual activity due to the risk of inciting bleeding.


Question 52

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Placental abruption

Answer 52

Placental abruption is the cause of 31% of cases of third trimester vaginal bleeding.

Most commonly characterized by vaginal bleeding with associated abdominal pain, uterine contractions, and a non-reassuring fetal heart tracing.

Abruption occurs when the placenta peels away from the inner wall of the uterus before delivery - either partially or completely - and can occur spontaneously or after trauma.

Abruptions can vary in size, from small and self-limited to near-complete separation of the placenta from the uterus.

Requires immediate medical treatment, as abruption can deprive the fetus of oxygen and cause heavy bleeding in the mother.

Question 53

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Bacterial vaginosis

Answer 53

Bacterial vaginosis, caused by a shift in the normal bacterial flora of the vagina, is often associated with thin, clear or mildly colored discharge, often with a foul odor.

Recent intercourse can be associated with bacterial vaginosis along with the use of douches or other artificial substances in the vagina.

Women with bacterial vaginosis sometimes complain of itching or dysuria, sometimes making it difficult to distinguish bacterial vaginosis from urinary infection or candiasis based on history alone.

Question 54

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Vaginal candiasis

Answer 54

Vaginal candiasis typically presents as itching in the vaginal and labial area with associated thick, whitish vaginal discharge.

Is common in pregnancy, is often associated with dysuria, and can be associated with recent sexual intercourse.

Question 55

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: UTI

Answer 55

Dysuria and lower abdominal discomfort are common symptoms of urinary tract infection, and recent sexual intercourse has been associated with urinary tract infection.

Question 56

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Cervical trauma

Answer 56

Cervical trauma can cause vaginal bleeding and can be associated with intercourse.

Question 57

Differential of Third Trimester Vaginal Discharge / Possible Vaginal Bleeding: Less Likely Diagnoses

Answer 57

Premature rupture of membranes (PROM) refers to rupture of the fetal membranes prior to the onset of labor and can occur at any gestational age - even at 42 weeks’ gestation and occurs in 8-10% of term pregnancies. Rupture of membranes typically presents as a large gush or steady trickle of clear vaginal fluid. Preterm PROM (defined as PROM prior to 37 weeks of gestation) is the leading identifiable cause of premature birth and accounts for approximately 18% to 20% of perinatal deaths in the United States. Therefore it is an important diagnosis to consider.

Preterm labor (prior to 37 weeks) is the leading cause of infant mortality in the United States.

Uterine rupture is a serious, but uncommon cause of second and third trimester vaginal bleeding. It occurs more often during delivery than prior to it. Uterine rupture is defined as a full-thickness separation of the uterine wall and the overlying serosa. It is associated with clinically significant uterine bleeding, fetal distress, expulsion or protrusion of the fetus, placenta, or both into the abdominal cavity, and the need for prompt cesarean delivery, uterine repair, or hysterectomy.

Question 58

Screening for gestational diabetes

Answer 58

usually performed between 24 and 28 weeks gestation, using a fasting glucose and a one-hour glucose following a 50g glucose load.
If the fasting glucose is greater than 126 mg/dL, OR the one-hour glucose is greater than 130mg/dL (90% sensitivity) or 140mg/dL (80% sensitivity), then the patient is considered to have a positive result.
In the case of a positive one-hour glucose, the patient should undergo a three-hour GTT with a 100g glucose load.

Question 59

Rhogam

Answer 59

If a pregnant woman is Rh-, she is given Rhogam (anti-Rh antibodies) in order to prevent sensitization of her immune system to the fetus’ Rh+ antigens.
Rhogam is given at 28 weeks gestation, within 72 hours post delivery, or with any episode of vaginal or intrauterine bleeding.
If untreated, the antibody containing blood of a sensitized Rh- mother may cross the placenta and cause hemolytic anemia in her Rh+ fetus