Early pregnancy disorders and miscarriage Flashcards
What is the embryonic period
Fertilisation to 10th week gestation
What is the germinal stage
First 2 weeks from fertilisation
When does implantation occur
8-10 days post fertilisation
What toxic exposures are the embryo exposed to during first trimester
Alcohol, drugs, other toxins
Infection eg. rubella, cytomegalovirus
Radiation
Nutritional deficiencies
Describe the week 4 embryo
Notochord formed in centre of embryonic disc
Gastrulation
Neural groove over notochord, brain bulge at one end
Neuromeres appear
Somites form
Primitive heart tube forming
Vasculature begins in embryonic disc
Describe the week 6 embryo
Measures 4mm Heart bulges, further develops, begins to beat regularly Septum primum appears Pharyngeal arches from Neural tube closes Ears begin as otic pits Arm buds and tail visible Lung buds appear Hepatic plate appears Buccopharyngeal membrane ruptures Cystic diverticulum + dorsal pacreatic bud appear Urorectal septum begins to form
Describe the week 7 embryo
8mm Optic vessels and cups form Nasal pits form Brain divides into 5 vesicles Leg buds form, hand paddles Rudimentary blood moves through primitive vessels Metanephros starts to develop Initial stomach differentiation begins
What is the fetal period
From 10th week gestation
All structures are formed, now develop
Not as sensitive to environmental exposure
Describe the week 10 fetus
30-80mm Ventral + dorsal pancreatic buds fuse Intestines rotate Facial features develop Head half fetus size Tooth buds appear Limbs long and thin Red blood cells produced in liver Heartbeat detected by ultrasound
Describe week 10-18 fetus
~15cm Fine hair develops on head Fetal skin almost transparent Fetus makes active movements Meconium made in intestinal tract Liver + pancreas produce fluid secretions
Describe week 18 fetus
20cm Lanugo covering whole body Nails, eyelashes More active, increased muscle development Quickening Heartbeat detected by stethoscope
What is miscarriage
Spontaneous loss of pregnancy before viability (24 weeks)
What are the classifications of miscarriage depending on gestation
Biochemical
Early pregnancy loss
Late pregnancy loss
What are the risk factors for miscarriage
Gestational age (<6 weeks 25%, >12 weeks 1-2%) Chromosomal abnormality Maternal + paternal age Previous miscarriage Pre-pregnancy weight Alcohol intake Smoking
What are the types of miscarriage
Threatened Inevitable Incomplete Complete Septic Anembryonic Missed
What is the ultrasound criteria for diagnosis of miscarrage
Crown-rump length 7mm but no heartbeat
Gestational sac diameter 25mm with no embryo
Absence of embryo with heartbeat 2 weeks after gestational sac with no yolk sac
Absence of heartbeat 11 days after gestational sac with yolk sac
What are the stages of miscarriage
- Ultrasonography showing early anembryonic pregnancy (missed miscarriage)
- Vaginal bleeding (threatened miscarriage)
- Open cervical os (inevitable miscarrage)
- Products of conception expelled, cramps, then bleeding subsides (miscarriage)
- Ultrasonography shows uterine contents- decidua, blood, some villi
What is recurrent miscarriage
Loss of 3 or more consecutive pregnancies
What are the risk factors of recurrent miscarriage
Environmental- maternal age, previous miscarriage, obesity, alcohol, smoking, caffeine
Antiphospholipid antibody- inhibits trophoblast function + complement activation
Genetic factors- balanced translocation
Anatomical factors (uterine malformations, cervical weakness)
Endocrine factors (uncontrolled diabetes, thryoid dysfunction)
Immune factors- uNK cells
Infection
Thrombophilia
How is recurrent miscarriage investigated
Referral to specialist clinic Antiphospholipid tests Cytogenetic analysis Pelvic ultrasound to assess uterine anatomy Thrombophilia tests
What is an ectopic pregnancy
Pregnancy outside of the uterine cavity
11/1000 pregnancies
What are the types of ectopic pregnancy
Tubal, ovarian, cervical, abdominal
What are common symptoms of ectopic pregnancy
Abdominal/pelvic pain Amenorrhoea Vaginal bleeding with/without clots Dizziness/fainting/syncope Shoulder tip pain Passage of tissue Pelvic tenderness Adnexal tenderness Abdominal tenderness
What is a hydatidiform mole
Growth of abnormal fertilisation
Complete mole- 2 sets of paternal genes, no maternal genes, no fetus
Partial mole- 3 sets of genes, 1 maternal, 2 paternal. Non-viable fetus
