Clinical overview
"Can I travel?" is one of the commonest questions a pregnant woman asks, and it is a deceptively rich consultation. The answer is almost never a flat yes or no — it is a structured, individualised risk assessment delivered in clinic. Good counselling takes a generic worry and turns it into specific, defensible advice: the right gestation to travel, the venous-thromboembolism (VTE) precautions appropriate to this woman's risk profile, the malaria and other infectious risks of her destination, the seatbelt and hydration advice for the journey itself, and — crucially — a plan for what she does if something goes wrong far from her booked facility.
For the South African registrar, travel counselling is not an abstract exercise in low-risk lifestyle medicine. South Africa has a high background burden of HIV, anaemia, hypertensive disease and obstetric haemorrhage; women travel long distances by minibus taxi and bus to visit family over December and Easter, often into provinces with seasonal malaria transmission (Limpopo, Mpumalanga lowveld, northern KwaZulu-Natal) or across borders into high-transmission southern African countries. The same woman who asks about a flight to London may equally be planning a 1,200-km road trip to the Eastern Cape over the festive season, delivering her not into a tertiary unit but into a district hospital or community health centre many hours from referral. Good advice therefore weds the international evidence to the realities of the South African health system, its levels of care and its referral pathways. This chapter is framed around delivering that advice safely and comprehensively.
Core knowledge
The two dominant physiological hazards of travel
Two pregnancy physiology changes drive most travel-specific risk and should anchor your reasoning.
1. Hypercoagulability and venous stasis. Pregnancy is a prothrombotic state: rising fibrinogen, factors VII/VIII/X and von Willebrand factor, falling protein S, and acquired activated-protein-C resistance, compounded by venous distensibility and mechanical compression of the iliac veins by the gravid uterus. VTE is among the leading direct causes of maternal death in well-resourced settings, and the risk is elevated antepartum and markedly so postpartum. Prolonged immobility — the defining feature of long-haul flights and long road or rail journeys — adds venous stasis on top of this baseline, so the absolute VTE risk of travel, while small per trip, is meaningfully raised in pregnancy compared with the non-pregnant traveller. Any journey involving more than roughly four hours of immobility is conventionally treated as a "long-distance" trip for counselling purposes (standard teaching; flag as a working threshold, not a hard cut-off).
2. Reduced physiological reserve for hypoxia and dehydration. Commercial aircraft cabins are pressurised to an equivalent altitude of roughly 1,800–2,400 m, lowering inspired oxygen and producing a modest fall in maternal arterial oxygen saturation. A healthy pregnant woman with a normal haemoglobin tolerates this without fetal compromise. A woman with significant anaemia, sickle cell disease, pre-eclampsia with severe features, significant cardiorespiratory disease, or a growth-restricted/compromised fetus has less reserve, and this is where caution sharpens. Low cabin humidity, immobility and reduced fluid intake also promote dehydration, which aggravates both venous stasis and (theoretically) uterine irritability.
Gestational windows
There is broad, long-standing consensus — reflected in airline policy rather than a single trial — on when travel is most comfortable and lowest-risk:
- First trimester: travel is generally safe, but nausea, vomiting and fatigue are at their worst, and the background miscarriage rate is highest, so an early-pregnancy event abroad is not uncommon and is distressing far from home. This is reasoning to share, not a prohibition.
- Second trimester (roughly 14–28 weeks): the conventional "best window" — the woman feels well, the early-pregnancy risks have passed, and she is not yet near the threshold for preterm complications.
- Third trimester: the practical constraint becomes the destination's distance from obstetric care and airline cut-offs. Most airlines restrict flying in late pregnancy: as a rough guide, many carriers allow uncomplicated singleton travel up to about 36 weeks and multiple pregnancies to about 32 weeks, often requiring a doctor's letter from around 28 weeks. These are airline policies, not clinical guidelines — always tell the woman to confirm with her specific carrier, and document that you did.