Pregnancy Flashcards
Define Small for gestational age (SGA).
An infant with a birth weight <10th centile for its gestational age.
Define Fetal growth restriction (FGR).
When a pathological process has restricted genetic growth potential. This can present with features of fetal compromise including reduced liquor volume (LV) or abnormal doppler studies.
Define constitutionally small foetuses.
Identified by small size at all stages but growth following the centiles. No pathology is present.
Name 2 different types of growth restriction.
- Placenta mediated
2. Non-placenta mediated
Describe the role of head circumference (HC) and abdominal circumference (AC) in the diagnosis of the cause of growth restriction .
A symmetrically small fetus is more likely to be constitutionally small whilst an asymmetrically small fetus is more likely to be caused by placental insufficiency.
Describe the impact on placental insufficiency on the amniotic fluid volume.
Placental insufficiency can result in impaired fetal kidney function which will result in reduced amniotic fluid volume.
What medication should women that are high risk for pre-eclampsia be started on at 16 weeks gestation?
75mg of aspirin
What should be given If delivery is being considered between 24 and 35+6 weeks gestation?
Antenatal steroids
What is Red blood cell isoimmunisation?
The production of antibodies in response to an isoantigen present on an erythrocyte.the production of antibodies in response to an isoantigen present on an erythrocyte.
What antibodies are produced when the mother’s immune system is sensitised to antigens on fetal erythrocytes?
IgG
What is the result of Rhesus D isoimmunisation?
This causes the fetal immune system to attack and destroy its own RBCs, leading to fetal anaemia. This is termed haemolytic disease of the newborn (HDN)
If sensitising events occur what can be administered to prevent maternal isoimmunisation?
Anti- D immunoglobulin
What blood tests should be considered following a sensitising event?
- Maternal blood group antibody screen
2. Feto-materal haemorrhage (FMH) test
Describe the red blood cell isoimmunisation screening programme in the UK.
In the UK, all pregnant women have a maternal blood group (ABO and RhD typing), and an antibody screen performed at the booking visit (8-12 weeks gestation). This is repeated at 28 weeks.
When should women who test RhD- be offered routine antenatal anti-D prophylaxis?
(500 IU) at 28 and 34 weeks gestation. Some centres give a single (larger) dose at 34 weeks.
What are the complications of prolonged pregnancy?
Due to the increased potential for placental insufficiency, there is also a higher risk of fetal acidaemia and meconium aspiration in labour, and the need for instrumental or caesarean delivery.
The reduced oxygen and nutrient transfer due to placental degradation can deplete fetal glycogen stores, resulting in neonatal hypoglycaemia.
Describe the appearance of babies born in prolonged pregnancies.
Vernix on a newborn. Prolonged pregnancy babies are typically born with less vernix and drier skin.
When is the most reliable period of dating for foetal age?
Dating is recommended between 11+0 and 13+6 weeks gestation during the first trimester scan. This is most reliable as the fetus rarely shows signs of being constitutionally large or small until a later stage of gestation.
Describe the NICE management of prolonged pregnancy.
Membrane sweeps – can be offered from 40+0 weeks in nulliparous and 41+0 weeks in parous women.
Induction of labour – usually offered between 41+0 and 42+0 weeks gestation.
See here for more information.
Define miscarriage.
A loss of a pregnancy at less than 24 weeks’ gestation
Name some risk factors of 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
Describe how a women a woman experiencing a miscarriage would present.
The main presenting symptom of miscarriage is vaginal bleeding. This may include passing clots or products of conception.
How is the definitive diagnosis of a miscarriage confirmed?
transvaginal USS
Under what CRL and no fetal heart beat would result in a diagnosis of inconclusive miscarriage and a repeat scan required in 7 days?
7mm
If a fetal pole is not visible, but intrauterine pregnancy is confirmed with a gestational sac and yolk sac, the management depends on what?
mean sac diameter (MSD)
What diagnosis can be made if the MSD is >25mm?
Failed pregnancy
During a miscarriage, regardless of treatment type, if the patient is Rhesus negative and is greater than 12 weeks gestation, what is required?
anti-D prophylaxis
Describe the 3 methods of management for miscarriages.
- Conservative
- Medical: vaginal misoprostol (prostaglandin analogue) to stimulate cervical ripening and myometrial contractions. It is usually preceded by mifepristone 24-48 hours prior to administration.
- Surgical: Surgical management involves a manual vacuum aspiration with local anaesthetic if <12 weeks, or evacuation of retained products of conception (ERPC).
Name the 6 types of miscarriages.
- Threatened
- Inevitable
- Missed
- Incomplete
- Complete
What is the definition of recurrent miscarriage?
the occurrence of three or more consecutive pregnancies that end in miscarriage of the fetus before 24 weeks of gestation
Name a syndrome that, if left with no pharmacological interventions, result in the live birth rate being as low as 10%
Antiphospholipid Syndrome
Name the 2 main genetic factors contributing to the risk of recurrent miscarriage.
- Parental chromosomal rearrangements
2. Embryonic chromosomal abnormalities
Name 3 endocrine factors contributing to the risk of recurrent miscarriage.
- Diabetes
- Thyroid disease
- PCOS
Name 3 anatomical factors contributing to the risk of recurrent miscarriage.
- Uterine malformations
- Cervical weakness
- Acquired uterine abnormalities
Name 3 risk factors for recurrent miscarriage.
- Advancing maternal age
- Number of previous miscarriages
- Lifestyle
Define ectopic pregnancy.
Any pregnancy which is implanted at a site outside of the uterine cavity
