Early Pregnancy Problems
Basic embryology and placental development
- 4 weeks from last menstrual period
- Gestational sac 3mm in diameter
- Ectoderm, mesoderm and endoderm present
- 6 weeks
Yolk sac present
Gestational sac 20mm in diameter
Embryo less that 10 mm long
Ultrasound visualisation possible
Embryo in cylindrical form with head and tail end
Fetal heart pulsations present
Umbilical cord formed
- 8 weeks
- gestational sac 30-50mm in diameter
- Fetus 25mm in length
- Limbs well formed, toes and fingers present
- 12 weeks
Gestational sac 100mm in diameter
Fetus 90mm long
Primary development of all organs has occurred/p>
Bleeding in Early Pregnancy
- Diagnosis requires differentiation from an ectopic and various forms of miscarriage
- Miscarriage is classified and spontaneous abortion before 24 weeks gestation
- Miscarriage will be experienced by 1 in 4 women at some point in their lives
- Investigations involve pregnancy testing and ultrasound
- Ectopic pregnancy is diagnosed if the pregnancy test is positive and the uterine cavity is empty
- Transvaginal scanning allows detection of intrauterine pregnancy at an earlier stage than transabdominal scanning and can also directly visualise an ectopic pregnancy in the tube
Aetiology of spontaneous miscarriage
- Chromosomal or genetic factors
- Endocrine abnormalities e.g. luteal phase defect, thyroid disease
- Reproductive tract abnormalities e.g. cervical incompetence, congenital abnormalities of the uterus (bicornuate, unicornuate), submucous fibroids
- Infection e.g. listeria, toxoplasmosis, mycoplasma, bacterial vaginosis
- Maternal age, more common after 35
- Polycystic ovarian syndrome – higher rates of miscarriage possible due to higher levels of LH
- Antiphospholipid antibodies, includes lupus anticoagulant and anticardiolipin antibodies. This may impair trophoblast function partly by causing thrombosis of the uteroplacental vessels
- Thrombophilic defects e.g. Factor V Leiden mutation
- Systemic diseases e.g. SLE, chronic renal disease, Wilson’s disease, poorly controlled diabetes, thyroid disease
- Investigation is normally postponed until the woman has had three miscarriages
Categories of spontaneous miscarriage
- Threatened miscarriage – painless vaginal bleeding which may settle spontaneously with continuing pregnancy or progress into a n inevitable miscarriage. Results from bleeding from the placental site
- Inevitable miscarriage – bleeding is of variable quantity, cervical os is open as the uterus contracts trying to expel the conceptus. Pain is usually accompanied by cervical dilation
- (In)complete miscarriage - Incomplete when only part of the conceptus has been expelled. Complete when all of the products have been expelled. The cervical os is usually open in incomplete and closed in complete
Additional Classifications
- Blighted Ovum (Anembryonic pregnancy) – when placental tissue develops but not embryo develops in the gestational sac. Eventually this leads to an inevitable miscarriage
- Missed Miscarriage – when the embryo can be visualised but there is no fetal heart. Inevitably this will lead to a complete or incomplete miscarriage if left
- Live Miscarriage – when the fetal heart can still be identified in utero before expulsion of the products of conception
Complications of spontaneous miscarriage
- Severe haemorrhage
- DIC
- Infection (E. Coli, streptococci, salmonella, CMV, bacteroides)
Management of miscarriage
- Syntocinon (oxytocin and ergotamine) encourages uterine contraction and minimises blood loss
Ectopic Pregnancy
- Rising increase in incidence in the Western World due to
Tubal damage caused by PID
Tubal surgery including sterilisation and its reversal
Intrauterine contraception devices
Improved diagnosis
IVF
Smoking
- Poor fertility prognosis, 2/3 will never subsequently bear a live child and 12-18% will go on to have another ectopic
- Sites of implantation
- Fallopian tube
- Cornua of uterus
- Ovary
- Abdomen
- Cervix
- Caesarean section scar (becoming more common)
- Diagnosis
- Bleeding following a period of amenorrhoea
- Usually no cervical dilation
- Severe abdominal pain
- Shoulder tip pain
- Treatment
- Classically laparotomy and salpingectomy to arrest or prevent haemorrhage
- Less aggressive option is laprascopically salpingostomy (opening of the tube and evacuation of the ectopic pregnancy)
- Imperative to check contralateral tube as the state of which might affect the bearing on which procedure is carried out
- Important to follow b-hCG levels until they are undetectable to ensure ectopic doesn’t persist
- Other conservative treatments include,
- Direct injection of prostaglandins into the ectopic pregnancy
- Use of chemotherapy such as methotrexate to destroy the trophoblast
Hydatidiform Mole
- Complete moles are entirely of paternal origin as the result of the fertilisation of a bighted ovum with a haploid sperm, thus the karyotype is 46XX
- Partial mole is usually triploid, most commonly 69XXY, one haploid set of maternal chromosomes and two haploid sets of paternal chromosomes which results from dispermic fertilisation
- Malignant transformation to choriocarcinoma may occur (requires extended follow up)
- Shows very high levels of hCG
- Clinical presentation
-
- Vaginal bleeding
- Passage of tissue
- Exaggerated pregnancy symptoms
- Treatment
Uterine evacuation
Hyperemesis gravidarum
- May be due to increasing levels of hCG which peak at 12 wk
- No evidence for adverse outcome for fetus
- May be aggravated by iron supplementation
- Antiemetics may be required and first line drugs are antihistamines
- These women are at increased risk of thrombosis and thromboprophylaxis may be considered