9.8 Abnormal Pregnancies Flashcards
Define ectopic pregnancy
Pregnancy which the fertilised egg attaches in a location other than uterine endometrium
Ectopic pregnancy risk factors
- Previous tubal surgery
- Infertility
- Confirmed previous genital infection
- Past or current smoker
- Previous ectopic pregnancy
- Sexual promiscuity
- Sterilisation
- Documented tubal pathology
Ectopic pregnancy pathology
- invasion of tubal mucosa by trophoblastic villi
- most of growth occurs between mucosa and muscular layer of fallopian tube
- Invasion of small blood vessels -> extraluminal bleeding and haematoma formation
- Intraluminal bleeding -> haematosalpinx with bleeding and extrusion from the fallopian tube
- The conceptus produces chorionic gonadotropin which keeps the corpus luteum functional
- Progesterone secreted by the CL initiates decidualisation of the endometrium
- When the trophoblast and embryo die hormonal support of the decidua is lost
- With resultant sloughing of the decidual cast and bleeding
Ectopic pregnancy symptoms
- signs and symptoms 4–6 weeks after their last menstrual period
- LAP and guarding
- Vaginal bleeding
- Signs of pregnancy -> amenorrhea, nausea, breast tenderness, frequent urination
- Tenderness in the area of the ectopic pregnancy
- Cervical motion tenderness, closed cervix
- Interstitial pregnancies tend to present late, at 7–12 weeks of gestation, because of myometrial distensibility
Tubal rupture
- Acute course with sudden and severe LAP (acute abdomen)
- Signs of hemorrhagic shock (e.g., tachycardia, hypotension, syncope)
Miscarriage
Duration
Type
Duration
First-trimester(early) pregnancy loss
- intrauterine pregnancy within the first trimester up to 13 weeks
- most common type
Second-trimester pregnancy loss
- 13-20 weeks of gestation
Type
- Spontaneous (sporadic, recurrent)
- Induced (unsafe, therapeutic)
Miscarriage clinical description
Incomplete miscarriage
- persistent pregnancy tissue in the uterus after a diagnosis of pregnancy loss
Inevitable miscarriage
- miscarriage that cannot be avoided because the cervix is open, bleeding is heavy or increasing, and abdominal cramping is present
Missed abortion
- a nonviable pregnancy in the absence of symptoms
Threatened miscarriage
- patient experiencing bleeding in early pregnancy but without a clear diagnosis of pregnancy loss
Complete
- describe patients with an empty uterus after documentation of prior intrauterine pregnancy.
- important since an empty uterus can be seen by ultrasound in the setting of normal early pregnancy that is too early to visualize, miscarriage, or ectopic pregnancy
Septic miscarriage
- any miscarriage, spontaneous or induced, that is complicated by uterine infection
Miscarriage causes
Maternal
Fetoplacental
Miscellaneous
Maternal
Abnormalities of the reproductive organs
- Septate uterus
- Uterine leiomyomas
- Uterine adhesions
- Cervical incompetence
Systemic diseases
- diabetes mellitus, hyperthyroidism, hypothyroidism, genetic disorders, infections, autoimmune diseases
Fetoplacental
- chromosomal abnormalities
- congenital abnormalities
Miscellaneous
- Trauma
- Iatrogenic (e.g., amniocentesis or chorionic villus sampling)
- Environmental (exposure to toxins such as drugs or maternal smoking during pregnancy)
- Unknown
Gestational trophoblastic disease
Classification
- diseases arising from abnormal proliferation of placental trophoblast
- lead to excess in highly vascular placental tissue
1. Benign trophoblastic leisons (GTD)
- Hydatidiform mole
- Exaggerated placental type
- placental site nodule
- abnormal (non-molar) villous lesions
2. Malignant GTN
- Invasive mole
- choriocarcinoma
- placental site trophoblastic tumour
- epithelioid trophoblastic tumour
Hydatiform mole
Definition
2 types
Risk factors
Characteristics
- type of GTD resulting from abnormal fertilization of an egg that can invade the uterus and metastasize
Complete mole: a type of hydatidiform mole typically resulting from fertilization by a single sperm of an abnormal egg that lacks maternal chromosomes
Partial mole: a type of hydatidiform mole typically resulting from fertilization of an egg by two sperm or a diploid sperm
Risk factors
- prior molar preg
- age _<15 and _>35 years
- history of miscarriage and infertility
Characteristics
- Proliferates within the uterus without myometrial infiltration or hematogenic dissemination
- May undergo malignant transformation to an invasive mole
Complete mole
Pathophysiology
Clinical features
Pathophysiology:
- Hydropic degeneration of chorionic villi with concomitant proliferation of cytotrophoblasts and syncytiotrophoblasts → death of the embryo
Clinical features:
- Vaginal bleeding during the first trimester
- Uterus size greater than normal for gestational age
- Pelvic pressure or pain
- Passage of vesicles with grape-like appearance
- β-hCG-mediated endocrine conditions:
Theca lutein cysts
Preeclampsia (before the 20th week of gestation)
Hyperemesis gravidarum
Hyperthyroidism: Very high amounts of hCG may lead to
hyperthyroidism because the α-subunit of hCG structurally resembles TSH
Partial mole
Clinical features
- Vaginal bleeding
- Pelvic tenderness
- No change in uterine size
- β-hCG-mediated endocrine conditions (less common)
Choriocarcinoma
Definition
Aetiology
Pathophysiology
Clinical features
Def
- highly malignant GTN characterized by invasive, highly vascular, and anaplastic trophoblastic tissue without villi
- Has the tendency to metastasize to the lungs, vagina, CNS, liver, pelvis, GI tract, and kidneys
Aetiology
Choriocarcinoma is preceded by:
- Hydatidiform mole
- Spontaneous abortion or ectopic pregnancy
- Term or preterm gestation
Pathophysiology:
- Malignant transformation of cytotrophoblastic and syncytiotrophoblastic tissue
- Destructive growth into myometrium without chorionic villi → risk of haemorrhage and early metastasis (lung, vagina, brain, liver)
Clinical features:
- depend on disease extension and metastases location
- Postpartum vaginal bleeding and inadequate uterine regression after delivery
Additional symptoms according to the site of metastasis e.g.:
- Dyspnea, cough, or hemoptysis from metastases in the lungs
- Seizures, headaches from metastases in the brain
- Visible vascular lesions from metastases to the vagina
- β-hCG-mediated endocrine conditions (e.g., hyperthyroidism, theca lutein cysts)
Invasive mole
Definition
Aetiology
Pathophysiology
Clinical features
Def
- form of GTD characterised by malignant transformation of incomplete or complete mole
Aetiology:
- risk of progression to an invasive mole depends on the type of initial hydatidiform mole
- Complete mole: 15–20% risk of subsequent invasive mole
- Incomplete mole: < 5% risk of subsequent invasive mole
Pathophysiology:
- Trophoblasts infiltrate the myometrium → increased risk of uterine perforation, intraperitoneal haemorrhage, or infection
- Hematogenic dissemination leads to metastatic growth (including in the brain, lungs, and liver).
Clinical features:
- Often detected on routine posttreatment surveillance following a hydatidiform mole
- Less likely to cause haemorrhage from a metastatic site than choriocarcinoma
Problems that arise form inaccurate determination of GA (gestational age)
- Poor scheduling of antenatal care visits and targeted investigations/interventions
- Misdiagnosis of preterm labour or post-term pregnancy hence intervention for these conditions
- Missed diagnosis of fetal growth aberration (small- or large-for-gestational age, intra-uterine growth restriction)
** Early dating of pregnancy central to optimising management of pregnancy –> ideal is the first trimester else no later than 24w**
Define:
- Large for gestational age (LGA)
- Small for gestational age (SGA)
- Intrauterine growth restriction (IUGR)
Large for gestational age (LGA): expected fetal weight > p90 for the specific gestational age
Small for gestational age (SGA): expected fetal weight < p10 for the specific gestational age
Intrauterine growth restriction (IUGR): failure of the fetus to achieve its full genetic growth potential
(p=percentile)
When will the symphysis-fundus height suggest intra-uterine growth restriction
If any of the following are found:
- Slow increase in uterine size until one measurement falls under the 10th centile.
- Three successive measurements ‘plateau’ (i.e. remain the same) without necessarily crossing below the 10th centile
- A measurement which is less than that recorded two visits previously without necessarily crossing below the 10th centile
Confirmation of diagnosis – fetal biometry and EFW using ultrasound
Define preterm labour
Preterm labour is diagnosed when there are regular uterine contractions before 37 weeks of pregnancy, together with either of the following:
- Cervical effacement and/or dilatation
- Rupture of the membranes
Define preterm rupture of membranes
Preterm rupture of the membranes is diagnosed when the membranes rupture before 37 weeks, in the absence of uterine contractions
Risk factors for preterm labour & rupture of membranes
- History of preterm labour in past pregnancy
- Poor/no antenatal care
- Poor socio-economic circumstances
- Smoking, alcohol or other harmful substance use
- Poor nutrition
- Over-distension of the uterus
Etiology of preterm labour & rupture of membranes
Maternal factors:
- Intra-uterine infection/chorioamnionitis - commonest cause
- Other sites of infection –> e.g. urinary tract infection
- Uterine abnormalities –> congenital uterine malformations and leiomyomas
- Cervical incompetence/insufficiency
Fetal factors:
- Multiple pregnancy
- Polyhydramnios
- Anomalies of the fetus
Placental factors:
- Placenta praevia (placenta covers cervix)
- Abruptio placentae (placenta detaches form uterus)
How to calculate gestational age
- LNMP = 19 week
- Ultrasound = 20 weeks
- Ultrasound = 20 (18-22) weeks
- LNMP = 19 weeks #
- EDD = 40 weeks (expected date of delivery)
Define Post date pregnancy
- a pregnancy extending beyond expected date of delivery
- late term pregnancy lasting until _>41 weeks 6 days OR _> 287 days
This is still normal
Define post-term (prolonged pregnancy)
- pregnancy lasting until _> 42 weeks OR _> 294 days
- only 2% of pregnancies become post term
Prolonged pregnancy / Post term pregnancy
Placental changes
Amniotic fluid changes
Foetal changes
Placental changes
- ageing placenta
- calcifications -> ⬇️ placental flow
- infarctions
Amniotic fluid changes
- oligo-hydramnios = ⬇️ blood flow to foetal kidney
- presence of meconium
Foetal changes
- macrosomia
- intra-uterine malnutrition
Post term pregnancy Risks & complications
Fetal complications
Maternal complications
Fetal complications
- meconium aspiration
- intra-uterine fetal death
- oligohydramnios ➡️ risk for abruption
- macrosomia
- abnormal CTG’s
- ⬇️ umbilical artery pH
- ⬇️ apgar score at 5min
- dysmaturity syndrome ➡️ hypoglycaemia / seizures
Maternal complications
- need for assisted delivery (ventouse vs forceps)
- labour dystocia
- perinael injuries
- need for induction of labour ➡️ exposed to uterotonic drugs / multiple methodes
- psychological stress
- need for ceasarean deliveries
Define Breech presentation
Malpresentation occurs when foetal buttocks (podalic pole) are the presenting part at maternal pelvis
Causes of breech presentations
Uterine
- abnormal uterus
- uterine masses (myoma)
Fetal
- congenital abnormalities
- short cord
Pregnancy
- twins
- oligo or poli-hydramnios
- placenta praevia
Types of breech presentations
- complete breech
- frank breech
- footling
- kneeling
A & B low risk for prolapse
Know the pictures
Define Transverse lie
- foetus lies transversely in uterus
- neither head or breech is in the pelvis or iliac fossa
- very high risk for prolapse
Define Oblique lie
- foetus lies obliquely in uterus
- head or breech is situated in the iliac fossa
- will not be able to have a natural delivery
Define Unstable lie
- baby tends to change it’s position continuously
What factors contribute to transverse, oblique and breech lie?
Maternal factors:
- Conditions that prevent engagement of the presenting part
- Small pelvis
- Placenta preavia
- Pelvic tumors
- Abnormal uterus shape
Foetal factors
- Twins
- Foetal abnormalities
- Polyhydramnios
- Large baby
- Prematurity
