Clinical overview
"High-risk pregnancy" is not a diagnosis — it is a working judgement that a particular woman, by virtue of her age, parity, past obstetric performance or a coexisting condition, carries a materially higher probability of an adverse maternal or perinatal outcome than the unselected obstetric population. The whole point of risk stratification is action: it changes where she should book and deliver (the appropriate level of care), how often she is seen, what is screened for, and what is anticipated at delivery. For the FCOG(SA) candidate, this objective is squarely a higher-order-thinking-skills (HOTS) topic — you are not asked to list dangers but to reason about why a given demographic carries a given risk, how large that risk is in rough terms, and what you would do differently in a South African district, regional or tertiary setting.
The recurring South African theme is that the demographics that drive risk here are not identical to those in high-income guidelines. We have a high burden of adolescent pregnancy, a large number of grand multiparous women in rural districts, a maternal HIV seroprevalence that reshapes almost every risk category, and a referral system stratified by level of care where the central skill is recognising the woman who must not deliver at the clinic. The leading direct and indirect causes of maternal death in the Saving Mothers reports — obstetric haemorrhage, hypertensive disease, and non-pregnancy-related infection (chiefly HIV) — concentrate disproportionately in exactly these higher-risk groups. Effective risk assessment at booking is therefore the single highest-yield preventive intervention in obstetrics.
Core knowledge
Advanced maternal age (AMA)
Advanced maternal age is conventionally defined as 35 years or older at the expected date of delivery, with a further "very advanced" stratum sometimes set at ≥40 or ≥45. The risks rise on a continuum rather than at a threshold, and they are partly biological (ageing oocytes, ageing vasculature) and partly because comorbidity accumulates with age.
The mechanisms worth holding in your head:
- Aneuploidy rises steeply because of increased meiotic non-disjunction in ageing oocytes. The risk of trisomy 21 at term is classically quoted around 1 in 1,500 at age 20, ~1 in 350 at age 35, and ~1 in 100 by age 40 (standard teaching — treat as orders of magnitude, not exact). This is the historical basis for offering aneuploidy screening and counselling and for the age-35 cut-off itself.
- Hypertensive disease and pre-eclampsia are more common, partly through stiffer maternal vasculature and a higher baseline prevalence of chronic hypertension.
- Gestational and pre-existing diabetes increase with age and with the rising BMI that often accompanies it.
- Placental dysfunction — both placental insufficiency causing fetal growth restriction and, at the other extreme, abruption and praevia — is commoner.
- Stillbirth risk rises modestly but consistently with maternal age, independent of comorbidity, which is one reason some services consider timed delivery around term in older women.
- Operative delivery (caesarean and instrumental) rates are higher, reflecting both medical indications and reduced myometrial efficiency.
Teenage / adolescent pregnancy
Adolescent pregnancy (broadly <18, with the highest risk <16 or within ~2 years of menarche) is a major South African public-health issue. The risks are a blend of biological immaturity and powerful social determinants.
- Pre-eclampsia and eclampsia are over-represented in primigravid adolescents — nulliparity itself is a pre-eclampsia risk factor and adolescents are usually nulliparous.
- Preterm birth and low birth weight are commoner.
- Cephalopelvic disproportion and obstructed labour are a real concern in the very young whose pelvis has not completed growth, with the historic downstream risk of obstetric fistula where labour is neglected.
- Anaemia and undernutrition are frequent and compound haemorrhage risk.
- Mental health — depression, anxiety and the consequences of coercion or gender-based violence — must be actively screened for; adolescent pregnancy is frequently non-consensual or exploitative, which has child-protection and legal implications.
- Late booking, poor attendance, and disengagement are the rule rather than the exception, so a single contact must achieve a great deal.
Grand multiparity
Grand multiparity is classically para 5 or more (≥5 previous births beyond viability); "great-grand multiparity" is sometimes set at ≥10. It remains common in parts of rural South Africa.
- Postpartum haemorrhage from uterine atony is the signature risk — the multiply-stretched, fibrotic myometrium contracts poorly. Grand multiparas are also at higher risk of uterine rupture, particularly with injudicious oxytocin.
- Malpresentation and unstable lie are commoner because of lax abdominal and uterine tone.
- Placenta praevia and abnormally adherent placenta rise with each successive pregnancy and with the scars of previous deliveries.
- Anaemia from repeated pregnancies and short inter-pregnancy intervals.
- Pre-existing hypertension and diabetes, simply because these women are often older as well as higher-parity.
Elderly primigravida
The elderly primigravida — a first pregnancy at an older age (a soft cut-off around ≥35, often used for ≥40) — concentrates the risks of both advanced age and nulliparity. She carries the AMA package above plus the nulliparous excess of pre-eclampsia and of dysfunctional labour, and she is frequently a precious pregnancy after subfertility or assisted reproduction (itself associated with multiple pregnancy and placental disorders). The combination justifies a low threshold for obstetrician-led care.
Poor obstetric history
This is the most powerful single predictor because the best guide to the next pregnancy is the last one. "Poor obstetric history" is an umbrella for events that tend to recur or that flag an underlying condition:
- Previous stillbirth or early neonatal death — recurrence risk is elevated and is the strongest driver of anxiety and of intervention.
- Recurrent miscarriage — see recurrent pregnancy loss; flags antiphospholipid syndrome, uterine anomaly, parental chromosomal rearrangement.
- Previous pre-eclampsia — substantially raises the risk of recurrence and is a hard indication for aspirin prophylaxis.
- Previous preterm birth or mid-trimester loss — the strongest predictor of recurrent preterm birth; may flag cervical insufficiency warranting cerclage assessment.
- Previous FGR or abruption — placental disorders recur.
- Previous caesarean(s) — drives the VBAC versus repeat caesarean decision and raises praevia/accreta risk.
- Previous severe PPH, obstetric anal sphincter injury, or shoulder dystocia — each changes planning for the index delivery.
- Rhesus or red-cell antibody sensitisation — see Rh isoimmunisation.
Figure I4.1 — High-risk pregnancy risk map linking age, parity and poor obstetric history to predictable complications.
Assessment
Risk assessment is a continuous process, but it is anchored at the first antenatal visit. The South African National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024) and the booking process are designed precisely to triage women into the correct level of care early.
History — the heart of this objective
Take a structured obstetric history that explicitly captures every component above:
- Age (calculate age at EDD, not at booking).
- Gravidity and parity — and for each previous pregnancy: gestation at delivery, mode of delivery, birth weight, outcome (live/still/neonatal death), and any complication (pre-eclampsia, PPH, abruption, OASIS, shoulder dystocia, GDM).
- Inter-pregnancy interval.
- Medical comorbidity — hypertension, diabetes, cardiac/renal disease, epilepsy, thyroid disease, and crucially HIV status and ART history (HIV in pregnancy).
- Social and mental-health screen — partner support, intimate-partner violence and mental health, substance use, and, in adolescents, age of partner and consent.
Examination and investigations
- Booking observations: BP, weight/BMI, accurate dating (early ultrasound is the most reliable method).
- Baseline bloods per the SA guideline schedule: haemoglobin, blood group and antibody screen, HIV (with same-day ART initiation if positive), syphilis (RPR), rubella where relevant, Rhesus typing.
- Targeted screening for the risk identified — e.g. glucose screening where there is a diabetes risk profile, aneuploidy screening discussion in AMA, a cervical-length pathway after previous preterm birth.
- Serial growth and well-being surveillance later in pregnancy (symphysis-fundal height, growth scans, Doppler) for the placental-insufficiency-prone groups.
The output of assessment is an explicit statement of risk level and the level of care at which the woman should be booked and should deliver — district (midwife-led/clinic), regional (specialist), or tertiary — with a documented referral plan. Getting this allocation right is the examinable judgement.
Figure I4.2 — Booking triage pathway converting high-risk history, screening and targeted tests into level-of-care decisions.
Management
Management is mostly about anticipation and placement: putting the right woman in the right place, screening for the predictable complication, and rehearsing the emergency before it happens.
Generic high-risk principles
- Right level of care. Use the SA guideline's referral criteria. As a rule of thumb, previous caesarean ×2 or more, previous stillbirth, significant medical disease, multiple pregnancy, and most "very advanced" maternal age belong at specialist (regional) or tertiary level; uncomplicated single risk factors may be co-managed with clear escalation criteria.
- Aspirin for pre-eclampsia prevention. Per NICE NG133, women at risk of pre-eclampsia — which includes nulliparity at extremes of age, previous pre-eclampsia, chronic hypertension, diabetes, and several of the groups above — should be offered low-dose aspirin (75–150 mg daily) from 12 weeks until delivery. This is one of the few cheap, high-impact interventions and is examinable.
- Calcium supplementation in low-dietary-calcium populations (relevant to much of South Africa) is recommended to reduce pre-eclampsia severity per WHO/SA guidance (standard teaching — confirm the local dose).
- Anaemia correction — iron and folate, with a low threshold to investigate and treat, because anaemia magnifies the consequences of any haemorrhage.
- Glycaemic and BP control where these coexist.
- Timed surveillance and delivery — growth-restriction-prone pregnancies get serial growth and Doppler; many high-risk pregnancies are delivered at or slightly before term to pre-empt late stillbirth, individualised to the risk.
By category
- Advanced maternal age / elderly primigravida: offer aneuploidy screening and counselling; aspirin; screen for diabetes and hypertension; growth surveillance; obstetrician-led delivery planning with a discussion of induction/elective delivery around term.
- Adolescent: a youth-friendly, non-judgemental service; aggressive anaemia and nutrition management; pre-eclampsia vigilance; mental-health and GBV screening; contraception and a postpartum contraception plan agreed antenatally; child-protection escalation where the pregnancy is the product of abuse.
- Grand multiparity: deliver where PPH can be managed; active management of the third stage with a uterotonic is non-negotiable; have oxytocin and second-line agents ready, secure IV access, group-and-save/cross-match per anaemia; careful, restrained use of oxytocin in labour because of rupture risk; have a low threshold for examining for malpresentation.
- Poor obstetric history: tailor to the index event — aspirin and possibly cervical surveillance/cerclage after previous preterm loss; specialist-led care and a clear delivery plan after previous stillbirth (commonly planned delivery near term); the VBAC discussion after previous caesarean; anti-D and antibody surveillance for sensitisation risk.
Emergency readiness — make the drill unmistakable
Two emergencies cluster in these groups and must be reflexive:
Postpartum haemorrhage (especially the grand multipara). Call for help. Apply the E-MOTIVE approach: Early detection (a calibrated drape), then in parallel — uterine Massage, Oxytocic (IV oxytocin first-line per SA EML; add second-line agents), Tranexamic acid 1 g IV (give early — the WOMAN trial showed benefit only when given within 3 hours of onset), IV fluids and resuscitation, and Examine the genital tract and escalate (bimanual compression, balloon tamponade, theatre). Do not wait for shock to declare. See postpartum haemorrhage.
Eclampsia / severe pre-eclampsia (the adolescent or elderly primigravida). Magnesium sulphate is the anticonvulsant of choice (loading then maintenance per NICE NG133/SA guideline), control severe hypertension, and plan delivery. See pre-eclampsia and HELLP and hypertension in pregnancy.
Antenatal counselling should rehearse the warning symptoms (severe headache, visual disturbance, epigastric pain, reduced fetal movements, bleeding) and the exact route to care, because in these groups late presentation kills.
Figure I4.3 — High-risk pregnancy management ladder with PPH and severe pre-eclampsia/eclampsia emergency drills.
Red flags / pitfalls
- Treating a label as reassurance. A "low-risk" booking does not stay low-risk; risk assessment is dynamic and must be repeated at every visit. Conversely, do not let the "high-risk" tag breed fatalism — most of these women have normal outcomes when surveillance is good.
- Missing the highest-risk number — previous obstetric outcome. Failing to elicit a previous stillbirth, pre-eclampsia or preterm birth is the commonest avoidable error; it changes aspirin, level of care, surveillance and delivery timing.
- Forgetting that nulliparity plus extremes of age compounds. The elderly primigravida and the adolescent primigravida are double-hit for pre-eclampsia and dysfunctional labour, not single-hit.
- Injudicious oxytocin in the grand multipara — augmenting a multiparous labour without watching for obstruction or rupture is dangerous; the multiparous uterus ruptures more readily.
- Under-resuscitating PPH in the anaemic woman. Grand multiparas and adolescents are often anaemic at baseline, so they decompensate at smaller blood losses — estimate loss generously and resuscitate early.
- Allocating the wrong level of care / late referral. The single most preventable adverse outcome in the SA system is the high-risk woman who delivers at a clinic that cannot manage the predictable complication. Refer early and document the plan.
- Neglecting the social and safeguarding dimension in adolescents — failing to screen for coercion, GBV and mental illness, and failing to plan contraception, is a missed opportunity with real consequences.
- Over-medicalising a healthy older woman to the point of unnecessary intervention — risk assessment guides surveillance, not reflexive caesarean.
Evidence anchors
- National Integrated Maternal and Perinatal Care Guideline (NDoH, 2024), NDoH South Africa — the SA source of truth for risk classification, level-of-care/referral criteria, the booking visit schedule and baseline investigations.
- Saving Mothers / NCCEMD reports (latest triennium) — define the leading SA maternal-death causes (obstetric haemorrhage, hypertension, non-pregnancy-related infection/HIV) that concentrate in these high-risk groups; the basis for prioritising risk assessment.
- NICE NG201 — Antenatal care (2021) — risk assessment, the content of booking, and identification of women needing additional care.
- NICE NG133 — Hypertension in pregnancy (2019) — low-dose aspirin 75–150 mg from 12 weeks for women at risk of pre-eclampsia; magnesium sulphate for severe pre-eclampsia/eclampsia.
- RCOG GTG 52 — Prevention and Management of Postpartum Haemorrhage and the WOMAN trial (Lancet 2017) (tranexamic acid 1 g IV within 3 h) and E-MOTIVE bundle (NEJM 2023) — emergency management relevant to the grand multipara.
- RCOG GTG 31 — Small-for-Gestational-Age and Growth-Restricted Fetus — surveillance pathway for the placental-insufficiency-prone groups (AMA, previous FGR).
- RCOG GTG 45 — Birth after Previous Caesarean Birth (VBAC) — decision-making for the poor-obstetric-history (previous caesarean) group.
- WHO antenatal care and pre-eclampsia-prevention recommendations — calcium supplementation in low-intake populations (confirm local dose against the SA guideline).
Notes on hedged facts: the per-age aneuploidy figures, the grand-multipara/great-grand-multipara parity cut-offs, the adolescent age thresholds, and the calcium dose are stated as standard teaching/orders of magnitude and are not line-item-cited; confirm exact thresholds against the current SA guideline before quoting in an exam answer.