obstetrics Flashcards
gravidity
Number of times a woman has been pregnant regardless of outcome
parity
Number of times a woman has given birth to a foetus (gestational age >/=24 weeks) regardless of whether the child was born alive or was stillborn
estimating gestation
Naegele’s rule: to the first day of the LMP add 1 year, subtract 3 months, add 7 days)
crown-rump length(CRL): measured by ultrasoundscan between 10+0 and 13+6
CV changes in pregnancy
SV up 30%, HR up 15% & cardiac output up 40%
systolic BP is unaltered
diastolic BP is reduced in the 1st and 2nd trimester, returning to non-pregnant levels by term
enlarged uterus may interfere with venous return which can lead to ankle oedema, supine hypotension and varicose veins
resp changes in pregnancy
Pulmonary ventilation up by 40%, tidal volume from 500 - 700ml (due to effect of progesterone on respiratory centre)
Oxygen requirements increase by only 20%, therefore over breathing leads to a fall in pCO2 - this can give rise to a sense of dyspnoea that may be accentuated by elevation of the diaphragm
BMR up 15% - this may be due to increased thyroxine and adrenocortical hormones - women may hence find warm conditions uncomfortable
haem changes in pregnancy
Maternal blood volume up 30%, mostly in 2nd half
red cells up 20% but plasma up 50% → Hb falls
Low grade increase in coagulant activity
rise in fibrinogen and Factors VII, VIII, X
fibrinolytic activity is decreased - returns to normal after delivery (placental suppression?)
prepares the mother for placental delivery
leads to increased risk of thromboembolism
Platelet count falls
WCC & ESR rise
urinary system changes in pregnancy
blood flow increases by 30%
GFR increases by 30-60%
salt and water reabsorption is increased by elevated sex steroid levels
urinary protein losses increase
trace glycosuria is common due to the increased GFR and reduction in tubular reabsorption of filtered glucose
biochem changes in pregnancy
calcium requirements increase during pregnancy
especially during 3rd trimester + continues into lactation
calcium is transported actively across the placenta
serum levels of calcium and phosphate actually fall (with fall in protein)
ionised levels of calcium remain stable
Gut absorption of calcium increases substantially - due to increased 1,25 dihydroxy vitamin D
liver changes in pregnancy
Unlike renal and uterine blood flow, hepatic blood flow doesn’t change
ALP raised 50%
Albumin levels fall
uterus development in pregnancy
100g → 1100g
hyperplasia → hypertrophy later
increase in cervical ectropion & discharge
Braxton-Hicks: non-painful ‘practice contractions’ late in pregnancy (>30 wks)
retroversion may lead to retention (12-16 wks), usually self corrects
baby blues features
typically seen 3-7 days following birth and is more common in primips, Mothers are characteristically anxious, tearful and irritable
baby blues mx
Reassurance and support, the health visitor has a key role
postnatal depression features
Most cases start within a month and typically peaks at 3 months, Features are similar to depression seen in other circumstances
mx postnatal depression
As with the baby blues reassurance and support are important. Cognitive behavioural therapy may be beneficial. Certain SSRIs such as sertraline and paroxetine may be used if symptoms are severe
puerperal psychosis features
Onset usually within the first 2-3 weeks following birth. Features include severe swings in mood (similar to bipolar disorder) and disordered perception (e.g. auditory hallucinations)
mx puerperal psychosis
Admission to hospital is usually required, ideally in a Mother & Baby Unit
screening for postnatal depression
The Edinburgh Postnatal Depression Scale
10-item questionnaire, with a maximum score of 30
indicates how the mother has felt over the previous week
score > 13 indicates a ‘depressive illness of varying severity’
sensitivity and specificity > 90%
includes a question about self-harm
when is the booking apointment
<10w
what happens at the booking appoitnment
education, lifestyle, nutrition
BMI
BP
urine dip
FBC
blood groupo
antibodies and rhesus D
screenin for thalassaemia and sickle cell
offer screenin for HIV, hepB, syphilis
what happens at 11-14w appointment
USS: gestational age, multiple pregnancy
offer anaomaly screening
what happens at the 18-20w appointment
USS: anomalies, placental location
24w scan
measure symothysis-fundal height
monitor hoetal movements
when is the ogtt
24-28w
28w appointment
give rhesus negative anti d
recheck fbc, blood group and antibody levels
discuss birth plans
36w appoiintment
abdo palpation for breech
USS
discuss delivery options
when will a mother be induced
41w
what is done at all antenatal appointments
BP
urine dip
wellbeing
vitamins in pregnancy
400 microgams folic acid, 10 micrograms vit D for all women
vaccines in pregnancy
Whooping cough, influenza (live attenuated vaccines CI)
who needs higher doses of vitamins
Women at high risk of neural tube defects require a higher dose of folic acid (5mgin the first trimester, in particular those with certain medical conditions which include:
Epilepsy
Previous baby with neural tube defects
Obesity with BMI over 35
Diabetes (Type 1 and 2)
Sickle cell disease
Thalassemia
Malabsorption disorders (e.g. Crohn’s disease)
Those taking folate antagonist drugs (HIV anti-retroviral drugs, methotrexate, sulphonamides)
It should be taken ideally 3 months before pregnancy and up to the first 12 weeks.
Offer all women Vitamin D (10 mcg) per day to reduce the risk of rickets. Women with darker skin, those from any BAME group (Black/Asian/Caribbean) or with a BMI >30 should have a higher dose.
combined test
11- 13+6 , USS and bloods Screens for trisomy 13 (Pataus), trisomy 18 (Edwards), trisomy 21
features on combined test suggesting downs syndrome
Nuchal translucency (thickened >6mm), BHCG (high), Pregnancy associated plasma protein A PAPP-A (low)
triple test
15-20w. alpha-fetoprotein unconjugated oestriol , human chorionic gonadotrophin .
triple test suggesting downs syndrome
alpha-fetoprotein (low), unconjugated oestriol (low), human chorionic gonadotrophin (high).
quadruples test
15-20w, alpha-fetoprotein ,unconjugated oestriol ), human chorionic gonadotrophin) and inhibin-A (high)
quadruple test suggesting down syndrome
alpha-fetoprotein (low), unconjugated oestriol (low), human chorionic gonadotrophin (high) and inhibin-A (high)
what to do if positive downs syndrome screening
Chorionic villous sampling (11-14 weeks)
Amniocentesis (15-20 weeks)
Non-invasive prenatal testing (private only)
key differentials for bleeding in early pregnancy
Miscarriage=
Ectopic pregnancy:
Molar pregnancy:
Antiphospholipid syndrome:
define miscarriage
loss of a pregnancy at less than 24 weeks’ gestation. Early miscarriages occur in the first trimester (<12-13 weeks) and are more common than late miscarriages, which occur at 13-24 weeks
ectopic pregnancy
any pregnancy which is implanted at a site outside of the uterine cavity
molar pregnancy
A molar pregnancy arises from anabnormalityin chromosomal number during fertilisation
antiphospholipid syndrome
An acquired disorder characterised by a predisposition to both venous and arterial thromboses, recurrent foetal loss and thrombocytopenia.
ix for bleeding in early pregnancy
History and examination (abdo, bimanual, speculum)
TVUS=gold standard
Bloods: serum b-HCG, FBC, blood group and rhesus status, if pyrexial=triple swabs and CRP
Pregnancy test
In EPAU
If molar pregnancy need histological examination of products of conception
most common site ectopic
ampulla of fallopian tube
RF miscarriage
Maternal Age >30-35 (largely due to an increase in chromosomal abnormalities)
Previous miscarriage
Obesity
Chromosomal abnormalities (maternal or paternal)
Smoking
Uterine anomalies
Previous uterine surgery
Anti-phospholipid syndrome
Coagulopathies
RF ectopic
Previous ectopic pregnancy
Pelvic inflammatory disease (due to adhesion formation)
Endometriosis (adhesion formation)
Intrauterine device or intrauterine system
Progesterone oral contraceptive or implant (due to fallopian tube ciliary dysmotility)
Tubal ligation or occlusion
Pelvic surgery – especially tubal surgery (reversal of sterilisation)
Assisted reproduction i.e. embryo transfer in IVF
RF molar pregnancy
Maternal age <20 or >35
Previous gestational trophoblastic disease (this risk is not decreased by a change of partner)
Previous miscarriage
Use of the oral contraceptive pill
sx antiphospholipid syndrome
Coagulation disorder (isolated raised APTT)
Livedo reticularis
Obstetric complications
Thrombocytopenia (low platelets)
diagnosis antiphospholipid syndrome
Antibody testing needs to be positive on 2 occasions 12 weeks apart
Lupus anticoagulant
Anticardiolipin antibodies
Anti-beta-2 glycoprotein I antibodies
partial molar pregnancy
where one ovum with 23 chromosomes is fertilised by two sperm, each with 23 chromosomes. This produces cells with 69 chromosomes (triploidy).
complete molar pregnancy
where one ovum without any chromosomes is fertilised by one sperm which duplicates, or (less commonly) two different sperm. This leads to 46 chromosomes of paternal origin alone.
These tumours are usually benign, but can become malignant – invading into the uterine myometrium, and disseminating around the body. These are known asinvasive moles.
sx ectopic pregnancy
pain-lower abdominal/pelvic pain, with or without vaginal bleeding. .
Shoulder tip pain– the irritation of the diaphragm by blood in the peritoneal cavity leads to referred shoulder tip pain.
Vaginal discharge– brown in colour, classically described as being akin to prune juice.
On examination, the patient may have localised
abdominal tenderness, with vaginal examination revealing cervical excitation and/or adnexal tenderness.
If the ectopic pregnancy has ruptured, the patient may also be
haemodynamically unstable(pallor, increased capillary refill time, tachycardia, hypotension), with signs of peritonitis (abdominal rebound tenderness and guarding). Vaginal examination may reveal fullness in the pouch of Douglas.
sx molar pregnancy
vaginal bleedingand abdominal pain early in pregnancy.
On examination, the uterus can be larger than expected for gestation, and of a soft, boggy consistency.
Hyperemesis– because there is an increased titre of B-hCG which is thought to be linked to nausea in pregnancy.
Hyperthyroidism –gestational thyrotoxicosis due to stimulation of the thyroid by high HCG levels.
Anaemia
Later in pregnancy, a ‘large for dates’ uterus may be noted on examination.
pregnancy of unknown location
Can’t be identified on ultrasound scan BUT β-HCG is positive
mx pregnancy unknown location
If the initialβ-HCGlevel is >1500 iUand there is no intrauterine pregnancy on transvaginal ultrasound, then this should be considered an ectopic pregnancy until proven otherwise, and a diagnostic laparoscopy should be offered.
If the initialβ-HCGlevel is <1500 iUand the patient is stable, a further blood test can be taken 48 hours later:
In a viable pregnancy, HCG level would be expected to double every 48 hours.
In a miscarriage, HCG level would be expected to halve every 48 hours
Where the increase or drop in the rate of change is outside these limits, an ectopic pregnancy cannot be excluded and the patient should be managed accordingly.
mx miscarriage
if the patient is Rhesus negative and is greater than 12 weeks gestation, they requireanti-D prophylaxis
Conservative (Expectant)
Medical management: vaginal misoprostol (prostaglandin analogue) to stimulate cervical ripening and myometrial contractions.
Surgical management: manual vacuum aspiration with local anaesthetic if <12 weeks, or evacuation of retained products of conception (ERPC)
mx ectopiuc pregnancy
Medical: IM methotrexate. For patients who: arestable, well controlled pain and β-HCG levels <1500 iU/ml, unruptured, andno visible heartbeat
Surgical management: laparoscopic salpingectomy
Conservative management: serum B-hCGshould be monitored every 48 hrs, patient must be stable with a small and unruptured ectopic
mx molar pregnancy
surgery, may need chemo
mx antiphospholipid syndrome
LMWH in pregnancy
features threatened miscarriage
Mild bleeding +/- PainCervix closed
TVUSS: Viable pregnancy
features inevitable miscarriage:
Heavy bleeding, clots, painCervix open
TVUSS: Internal cervical os openedFetus can be viable or non-viable
features missed miscarriage
Asymptomatic or hx of threatened miscarriage, on-going discharge, small for dates uterus
TVUSS: No fetal heart pulsation in a fetus where crown rump length is >7mm*
features incomplete miscarriage
POC** partially expelled – Sx of missed miscarriage or bleeding/clots
TVUSS: Retained POC, with A/P endometrial diameter >15mm AND proof that were was a intrauterine pregnancy previously present (USS/clinically remove clots)
features complete miscarriage
Hx of bleeding, passing clots and POC and pain. Sx settling/settled now
TVUSS: No POC seen in uterus, with endometrium that is <15 mm diameter AND previous proof of intrauterine pregnancy i.e. scan
features of a septic miscarriage
Infected POC: fever, rigors, uterine tenderness, bleeding/discharge, pain
TVUSS: Leucocytosis, raised CRP + can be features of complete or incomplete miscarriage
differetnials for antepartum haemorrhage
placenta praevia
placental abruption
vasa praevia
placenta praevia
placenta lying across OS
placental abruption
placental prematurely separates
vasa praevia
When foetal vessels lie outside the protection of the umbilical cord or placenta
presentation plaental abruption
sudden onset severe continuous abdominal pain, +-Antepartum haemorrhage, can be concealed if cervical os remains closed, Maternal haemodynamic instability, Foetal distress on CTG, Woody abdomen on palpation
presentation vasa praevia
Antepartum haemorrhage, Visible pulsating foetal vessels on cervical exam, Immediate bleed and foetal distress following ROM
presentation placental praevia
Usually detected on 20w USS / presents 24w+ with painless PV bleeding or asymptomatic until labour.
mx placenta pravia
Corticosteroids from 32-36w
Planned CS 36-37w to reduce risk of spontaneous labour and massive haemorrhage.
If already bleeding (antepartum haemorrhage) emergency CS required
mx vasa pravia
Corticosteroids from 32w.
Planned CS 34-36w.
mx placental abruption
ABCDE, obstetric emergency so immediately involve consultant.
2 grey cannulas + bloods (FBC, U&Es, LFTs, coag). And Crossmatch 4 units of blood.
Fluid and blood resus
Monitor mother and foetus
Corticosteroids, Anti-D prophylaxis if rhesus –ve mother
Emergency CS
abortion act
In the UK, termination of pregnancy (TOP) is governed by the The Abortion Act of 1967. There are five ‘categories’ for requesting TOP:
A. that the pregnancy has not exceeded its twenty-fourth week and that the continuance of the pregnancy would involve risk, greater than if the pregnancy were terminated, of injury to the physical or mental health of the pregnant woman or any existing children of her family.
B. that the termination is necessary to prevent grave permanent injury to the physical or mental health of the pregnant woman
C. that the continuance of the pregnancy would involve risk to the life of the pregnant woman, greater than if the pregnancy were terminated D. that there is a substantial risk that if the child were born it would suffer from such physical or mental abnormalities as to be seriously handicapped.
termination of pregnancy
Medical termination of pregnancy: Mifepristone, a progesterone antagonist, Followed by Misoprostol 48h later , a prostaglandin analogue.
Surgical termination of pregnancy: Suction termination, Dilatation and evacuation/curettage ‘D&C’
Choice loosely based of gestation
less than 9 weeks: medical management,
less than 13 weeks: surgical dilation and suction of uterine contents
more than 15 weeks: surgical dilation and evacuation of uterine contents or late medical abortion (induces ‘mini-labour’)
features polyhydramnios
uterus feels tense or large for dates, may be difficult to feel the foetal parts on palpation of the abdomen
cause of polyhydramnios
excessive production of amniotic fluid
insufficient removal of amniotic fluid.
Excess production can be due to increased foetal urination: Maternal diabetes mellitus, Foetal renal disorders, Foetal anaemia, Twin-to-twin transfusion syndrome
Insufficient removal can be due to reduced foetal swallowing: Oesophageal or duodenal atresia, Diaphragmatic hernia, Anencephaly, Chromosomal disorders
complications polyhyramnios
Maternal: respiratory compromise (increased pressure on the diaphragm), Increased risk UTIs due to increased pressure on the urinary system, Worsening of other symptoms associated with pregnancy such as gastro-oesophageal reflux, constipation, peripheral oedema and stretch marks, Increased incidence of caesarean section delivery, Increased risk of amniotic fluid embolism (although this is rare)
Foetal: Pre-term labour and delivery, Premature rupture of membranes, Placental abruption, Malpresentation of the foetus (the foetus has more space to “move” within the uterus), Umbilical cord prolapse (polyhydramnios can prevent the foetus from engaging with the pelvis, thus leaving room for the cord to prolapse out of the uterus before the presenting part)
mx polyhydramnios
Treatment includes management of any underlying causes (e.g. in maternal diabetes) and amnio-reduction in severe cases.
causes oligohydramnios
premature rupture of membranes
Potter sequence
bilateral renal agenesis + pulmonary hypoplasia
intrauterine growth restriction
post-term gestation
pre-eclampsia
pathophysiology rhesus disease
if a Rh -ve mother delivers a Rh +ve child a leak of fetal red blood cells may occur
this causes anti-D IgG antibodies to form in mother
in later pregnancies these can cross placenta and cause haemolysis in fetus
this can also occur in the first pregnancy due to leaks
mx rhesus disease
All mothers tested at booking
Anti-D immunoglobulin should be given as soon as possible (but always within 72 hours) of a sensitizing event
If known rhesus negative mother given routinely at 28 and 34 weeks
if event is in 2nd/3rd trimester give large dose of anti-D and perform Kleihauer test - determines proportion of fetal RBCs present
ix in rhesus disease
all babies born to Rh -ve mother should have cord blood taken at delivery for FBC, blood group & direct Coombs test
Coombs test: direct antiglobulin, will demonstrate antibodies on RBCs of baby
Kleihauer test: add acid to maternal blood, fetal cells are resistant
affects of rhesus disease on fetus
oedematous (hydrops fetalis, as liver devoted to RBC production albumin falls)
jaundice, anaemia, hepatosplenomegaly
heart failure
kernicterus
treatment: transfusions, UV phototherapy
sensitising events requiring anti d
Antepartum haemorrhage
Placental abruption
Abdominal trauma
External cephalic version
Invasive uterine procedures such as amniocentesis and chorionic villus sampling
Rhesus positive blood transfusion to a rhesus negative woman
Intrauterine death, miscarriage or termination
Ectopic pregnancy
Delivery (normal, instrumental or caesarean section)