Obstetrics: Physiology, Care & Complications

1. Obstetrics Phase 3A Freddie Hett and Gabby Zealand The Peer Teaching Society is not liable for false or misleading information.

2. Aims We will discuss: • Physiology of pregnancy • Aspects of normal pregnancy and antenatal care • Obstetric disorders and their management • Mechanisms of labour • Management of delivery • Complications in and around labour

3. Introduction and Plan Present information about different aspects of obstetrics. Lots of questions! (Both ways)Use visual aids. Summarise key points at the end.

4. Physiological Changes in Pregnancy The Peer Teaching Society is not liable for false or misleading information.

5. Antenatal Care Aims of antenatal care: • Detect and manage preexisting problems that might affect pregnancy • Prevent, detect and manage maternal complications • Prevent, detect and manage fetal complications • Detect congenital fetal problems • Plan circumstances of delivery with mother • Provide lifestyle education and advice (optimisation)

6. Gravidity and Parity Gravidity = number of times a woman has been pregnant.Parity = number of times a woman has given birth to a fetus >24 weeks (>20 weeks for some sources) Pregnant female patient aged 28. Currently undergoing her booking visit at 10 weeks.She currently has three children. Twin girls age 6. A young son aged 2.Unfortunately she has had two miscarriages. One at 13 weeks. One at 25 weeks.How would you grade this woman? Gravidity = 5 Parity = 3

7. Antenatal Schedule + Screening Booking visit should take place by 10 weeks. 10 visits for P0. 7 visits for >G1 USS @ 11 – 13 weeks for nuchal translucency + chorionicity (Fetal HF, chromosomal abnormalities, CNS defects, T21)AFP for teratomas, neural tube defect, TurnersAmniocentesis: amniotic fluid AFP is measured + cells cultured for karyotyping (neural tube defects, genetic disorders)

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9. Down’s Testing Combined test:Nuchal translucency +free beta HCG +pregnancy associated plasma protein+ patient’s age.Used between 10 weeks and 13 weeks.Amniocentesis offered to those ‘at high risk’.

10. Multiple Pregnancy Monozygotic Dizygotic MonochorionicDichorionic Two placentas Zygote divides after fertilisation Different oocytes fertilised by separate sperm. Shared placenta Monoamniotic or diamniotic? Do the twins share a sac or not?Dichorionic (~70%) can be MZ or DZ. Dichorionic are always diamniotic. Monochorionic, diamniotic (~30%) are always MZ. Share placenta but not sac.Monochorionic, monoamniotic (~1%) are always MZ. Share everything! Consider TTTS in MC twins (~15%, ~4.5% of all twin pregnancies)

11. Expected Date of Delivery (EDD) Naegele’s rule:Take the first day of the patient’s last period.Add 1 year to this date, subtract 3 months, add a further 7 days.(effectively add 9months + 7 days to date of last period!) USS dating is also used now (in first trimester)

12. Small for Gestational Age and IUGR Small for gestational age (SGA/SFD):<10th centile for gestation (no intervention if no deterioration, ie – growing normally)IUGR: Growth in utero has slowed, does not necessarily mean that they will end up SFD. Important factor as continued IUGR is indicative of pregnancy problems. Consider early delivery if continued IUGR.

13. Factors in Fetal Growth Constitutional determinants: • Low maternal weight and height • Asian ethnic group • Female gender baby Pathological determinants: • Pre-existing maternal disease • Cx of pregnancy • Multiple pregnancy • Smoking • Malnutrition • Congenital abnormalities Serial measurement of symphysis fundal height can help in diagnosis restricted growth. SFD/ SGA is definitively diagnosed with aid of USS.

14. Conditions in Pregnancy • Placenta praevia • Placental abruption • Ruptured vasa praevia • Placenta accreta/ percreta • Pre-eclampsia • Diabetes • VTE

15. Placenta Praevia The placenta is implanted in the lower segment of the uterus.Minor= in L segmentMajor= complete or partial covering of internal osIt is more common in twins and mothers of high parity and age. Obstructs engagement of head, necessitating LSCS. PPH is more common and severe as lower segment is less able to contract after delivery (atony). Keep blood available!

16. Placental Abruption Part, or all of the placenta separates before delivery. ~1% of pregnancies. Bleeding may remain internal and invisible.Common cause of IUFDIUGR and pre eclampsia are major risk factors Typical presentation:Clasically painful bleeding. Pain alone may indicate a concealed bleed. O/E patient may be tachy due to blood loss, and uterus is described as ‘woody’ hard if severe. Urgent CTG, FBC and cross match.DIC and renal failure are serious risks for the mother. Admit! IV fluid and consider transfusing.

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19. Ruptured Vasa Previa Fetal blood vessel runs in the membrane in front of presenting part. ROM can cause rupture of vesselLeads to painless PV bleed, and fetal distress. LSCS is often not quick enough to save the fetus.

20. Placenta Accreta and Placenta Percreta Placenta accreta describes a placenta that has implanted more deeply in the myometrium than normal. This makes it more difficult for the placenta to separate. This increases the risk of large PPHs as the myometrium struggles to contract sufficiently and stem bleeding post delivery. Placenta percreta describes placental implantation with penetration through into surrounding structures. Nearly always associated with excessive bleeding + PPH. Often necessitates emergency abdominal hysterectomy.

21. Pre-Eclampsia Proteinuria (>0.3g/24hr) + hypertension (>140mmHg) Multisystem disease with variable features. Cured only by delivery.Affects ~6% of nulliparous women. Disease mechanism not fully understood. Trophoblast invasion by spiral arterioles is incomplete leading to decreased utero-placental flow.Ischaemic placenta induces widespread endothelial cell damage leading to vasoconstriction and increased vascular permeability.

22. Pre-Eclampsia Risk factors: • Nulliparity • Previous/ family history • Obesity • Extremes of age • Preexisting microvascular disease Presentation: • Generally asymptomatic • Headaches, drowsiness and nausea in late stages • Hypertension is usually first sign • Oedema may be present • Epigastric tenderness is bad! Complications:Lots! Eclampsia (T-C seizures, Rx: MgSO4), CV haemorrhage, HELLP, renal failure, pulmonary oedema…

23. Pre-Eclampsia Fetal complications: • Pre-eclampsia accounts for 5% of still births and 10% of pre terms. • Principle problem is IUGR in pre-eclampsia <34 weeks. Management:Anti hypertensives given if BP >150/100. Urgent if >160/110. Labetalol recommended. (Why?) Anti hypertensives do not changes course of disease but help manage symptoms!MgSO4 prophylactically to prevent eclampsia.Sever pre-eclampsia requires urgent delivery. (Monitor for 24h after)<34 weeks then LSCS. >34 weeks; induce with prostaglandins.

24. Diabetes

25. Diabetes Glucose tolerance decreases in pregnancy due to altered carbohydrate metabolism. Pregnancy is ‘diabetogenic’. (Impaired glucose tolerance -> DM) Even slightly raised glucose levels have an adverse effect on pregnancy. Therefore treat at a lower threshold.NICE: fasting glucose >7mmol/L OR >7.8mmol/L 2hr after 75g glucose load (GTT)This definition encompasses 3.5% of pregnant women. Screening is very important! (28 weeks with GTT)

26. Fetal Complications of Diabetes • Congenital abnormalities (neural tube + cardiac) • Pre term delivery. • Fetal lung maturity reduced. • Increased birth weight and associated trauma • Fetal compromise and fetal distress are more common • Polyhydramnios -> increased chance of abruption • Hypoglycaemia post delivery as baby is ‘accustomed’ to hyperglycaemia.

27. Venous Thromboembolic Disease • Pregnancy is a ‘prothrombotic state’. • PE is an important cause of maternal death. • DVT in 1% of pregnant women. • Embolism in ~0.3%. (Mortality is ~3%) • Roughly a 1/10,000 chance of dying! • Treat VTE with LMWH. (Warfarin is teratogenic) • Ante natal rophylaxis should only be reserved for pregnancies deemed to be very high risk. • Postpartum prophylaxis is common and sensible! This is when most thromboembolic events occur.

28. Normal labour • What is normal labour? • Spontaneous onset • Low-risk • Vertex position • Between 37 and 42 weeks • Good condition after birth • (without induction of labour, spinal/epidural/general anaesthesia, forceps/ventouse/ caesarean delivery or episiotomy) The Peer Teaching Society is not liable for false or misleading information…

29. Normal labour • General care in labour: • Low BP? • Maternal positioning? • Hydration/ eating? • Pyrexia? • Urinary tract? • Psychological well-being The Peer Teaching Society is not liable for false or misleading information…

30. Normal labour • Phases of labour? • 1st stage • Latent phase • Active phase • Transitional phase • 2nd stage • From full cervical dilatation to birth • 3rd stage • After the foetus is expelled until just after the placenta is expelled The Peer Teaching Society is not liable for false or misleading information…

32. Normal labour • 3 Ps? • Powers • Too little – nulliparous, amniotomy, oxytocin • Too much – oxytocin, placental abruption, salbutamol • Passage • Cephalopelvic disproportion, pelvic mass, cervical incompetence The Peer Teaching Society is not liable for false or misleading information…

33. Passenger/ fetal presentation Normal presentation? The Peer Teaching Society is not liable for false or misleading information…

34. Abnormal fetal presentation • Other abnormal presentations? The Peer Teaching Society is not liable for false or misleading information…

35. Abnormal fetal presentation • Risk factors? • Prematurity, multiple pregnancy, abnormalities of uterus, fetal abnormality, placenta praevia, smoking, polyhydramnios/oligohydramnios, IUGR, prev. breech • Breech • Confirm with USS • ECV • C-section The Peer Teaching Society is not liable for false or misleading information…

36. Mechanism of labour • Descent • Flexion • Internal rotation • Crowning • Restitution • Internal rotation of shoulders • Anterior shoulder • Posterior shoulder • Lateral flexion The Peer Teaching Society is not liable for false or misleading information…

37. 3rd stage • Active/physiological • Active – uterotonic drugs, early clamping and cutting, controlled cord traction • Lower risk of PPH with active management • Retained placenta • Perineal trauma The Peer Teaching Society is not liable for false or misleading information…

38. Pain relief • Pain relief methods in labour? • Non-pharmacological • Entonox • Opioids • Pudendal nerve block • Epidural The Peer Teaching Society is not liable for false or misleading information…

39. Instrumental delivery • Most commonly due to prolonged second stage  1 hour of pushing has failed to deliver the baby • Maternal exhaustion • Fetal distress in 2nd stage The Peer Teaching Society is not liable for false or misleading information…

40. Instrumental/ operative delivery The Peer Teaching Society is not liable for false or misleading information…

41. Multiple pregnancy • Single fertilised egg divides (monozygotic) twins • Two or more ova fertilised (dizygotic) twins • In dizygotic each fetus has its own placenta, amnion & chorion • In monozygotic this depends on timing of division of ovum The Peer Teaching Society is not liable for false or misleading information…

42. Multiple pregnancy • Risk factors? • Previous multiple pregnancy, FH, assisted conception • Presentation? • Ultrasound, hyperemesis, enlarged uterus, polyhydramnios • Twin to twin transfusion syndrome • Monochorionic twins • Disproportionate bloody supply • Serial amniocentesis, laser therapy The Peer Teaching Society is not liable for false or misleading information…

43. Prematurity • Infants born before 37 weeks • Risk factors? • APH, multiple pregnancy, previous preterm birth, smoking, genital infection, cervical weakness • Diagnosis • Management? • Fetal fibronectin, cervical length scanning • Progesterone, Abx, tocolysis, corticosteroids The Peer Teaching Society is not liable for false or misleading information…

44. Postmaturity & induction • Beyond 41 weeks, placental function may decline and become insufficient • Risk factors? • Previous post-term pregnancy, high maternal BMI, primigravidity • May be reduced fetal movements • Increased risk of meconium aspiration, neonatal hypoglycaemia, fetal macrosomia The Peer Teaching Society is not liable for false or misleading information…

45. Induction of labour • CTG • Bishop’s score • Offer induction at 41 weeks • Methods of induction? • Sweep of the membranes, prostaglandin gel/pessary, ARM ± oxytocin • Complications? • Uterine hyperstimulation, uterine rupture, infection, prolapsed cord, amniotic fluid embolism The Peer Teaching Society is not liable for false or misleading information…

46. Puerperium • 6 week period following giving birth • Lochia • Problems? • Perineal pain • Urinary & bowel problems • Mastitis ± infection • Endometritis • Psychiatric • PPH – primary/secondary • Thromboembolism • Contraception The Peer Teaching Society is not liable for false or misleading information…

47. Obstetric emergencies • Uterine rupture • Eclamptic seizure • Haemorrhage • Cord prolapse • Sepsis • DIC • Amniotic fluid embolism • Fetal distress • Uterine inversion • Shoulder dystocia • PE • Placental abruption • Adrenal haemorrhage • HELLP syndrome The Peer Teaching Society is not liable for false or misleading information…

48. Uterine rupture • Presentation? • Constant pain and tenderness over uterus, vaginal bleeding (often small as intraperitoneal bleed), unexplained maternal tachycardia, shock, cessation of contractions, fetal distress • Bleeding from rupture  acute fetal hypoxia and massive haemorrhage • Commonly rupture in old scar The Peer Teaching Society is not liable for false or misleading information…

49. Uterine rupture • Risk factors? • Scarred uterus, classic caesarean, congenital uterine abnormalities, oxytocin use • IV fluids, cross match • Urgent laparotomy • Deliver baby by c-section The Peer Teaching Society is not liable for false or misleading information…

50. Shoulder dystocia • Inability to deliver the shoulders after the head has been delivered requiring additional manoeuvres • Risk factors? • Previous shoulder dystocia, large/ postmature fetus, increased maternal BMI/ maternal diabetes, induced labour, prolonged first/second stage , assisted vaginal delivery The Peer Teaching Society is not liable for false or misleading information…