High Risk Pregnancies

A framework for identifying and managing pregnancies carrying an elevated risk of adverse maternal or fetal outcome. The risk reflects relevant maternal medical conditions, previous obstetric history, or pregnancy-specific complications.

Structured, individualised risk assessment is performed at initial antenatal booking and reassessed throughout pregnancy. This is essential to directing appropriately intensified surveillance and specialist multidisciplinary involvement.

This entry provides the overarching risk stratification framework complementing the detailed, condition-specific management principles addressed under the numerous individual maternal and pregnancy-related conditions throughout this Atlas.

Classification of risk factors

• Pre-existing maternal medical conditions relevant to pregnancy risk include diabetes (both pre-existing and gestational), hypertension, renal disease and significant psychiatric illness.
• Significant cardiac disease is of particular relevance, given the substantial physiological cardiovascular demands of pregnancy.
• Autoimmune conditions include systemic lupus erythematosus and antiphospholipid syndrome.
• Each condition has specific implications for maternal and fetal risk and requires individualised, specialist joint management.
• Previous obstetric history relevant to current pregnancy risk includes previous pre-eclampsia, previous preterm birth, previous stillbirth or significant fetal growth restriction, and previous gestational diabetes.
• Previous caesarean delivery is relevant to placenta accreta spectrum risk in a subsequent pregnancy with placenta praevia.
• A relevant previous history in any of these areas generally warrants specific, targeted additional surveillance or prophylactic intervention in the current pregnancy.
• Pregnancy-specific risk factors identified during the current pregnancy include significant maternal obesity, advanced maternal age, and any identified fetal structural or chromosomal abnormality.
• Multiple pregnancy carries substantially elevated risk across numerous domains, including preterm birth, pre-eclampsia and fetal growth restriction.
• Any specific complication that develops during the pregnancy (including pre-eclampsia, gestational diabetes or placenta praevia) also counts.
• Social and demographic risk factors include significant social deprivation, limited engagement with antenatal care, domestic violence and substance use. They are important additional considerations in risk assessment and call for tailored, sensitive support and care planning.

• Risk assessment at initial antenatal booking, incorporating detailed medical, obstetric and social history with baseline clinical assessment, is the essential foundation. It identifies risk factors and directs individualised, risk-stratified care planning.
• The clinical presentation and features reflect the underlying condition or risk factor present, addressed under the detailed, condition-specific principles throughout this Atlas. High risk pregnancy is not a single, unified clinical presentation in itself.
• Risk status is not static. New risk factors or complications can emerge at any stage, so ongoing, dynamic reassessment is needed throughout pregnancy.
• Antenatal surveillance must remain responsive to evolving clinical circumstances rather than rely solely on the initial booking risk assessment.
• Cumulative risk, from multiple coexisting risk factors in the same pregnancy, warrants careful attention because risk can compound rather than simply add.
• This underscores the importance of holistic risk assessment rather than considering individual risk factors in isolation.

• Structured, full booking risk assessment, incorporating validated screening tools and established risk stratification criteria where available (including specific criteria used to guide aspirin prophylaxis for pre-eclampsia risk), forms the essential foundation of risk identification.
• Ongoing, structured reassessment at each subsequent antenatal contact, incorporating clinical assessment together with appropriately targeted investigation according to the specific, identified risk factors present, supports timely identification of any evolving complication requiring escalated care.
• Appropriately targeted, condition-specific investigation and monitoring, following the detailed diagnostic principles addressed under the relevant individual maternal and pregnancy-related conditions throughout this Atlas, is directed according to the specific pattern of risk factors identified in the individual pregnancy.

• Structured, individualised care planning is the essential, central management approach for high risk pregnancy.
• It incorporates appropriately intensified antenatal surveillance, including more frequent antenatal visits, additional growth ultrasound scanning, and targeted screening or monitoring relevant to the identified risk factors.
• It also involves specialist multidisciplinary team input where relevant to the maternal condition or pregnancy complication present.
• Prophylactic intervention, where evidence-based and relevant to the identified risk factor, is an important component of proactive, risk-appropriate management. Examples are low-dose aspirin for women at elevated pre-eclampsia risk and thromboprophylaxis for women with relevant risk factors for venous thromboembolism.
• Individualised delivery planning considers the optimal timing, mode and setting for delivery according to the risk factors and any evolving complications.
• Plan neonatal care where relevant, including access to appropriate level neonatal intensive care facilities for anticipated preterm delivery or other neonatal risk.
• Management of the underlying condition or complication contributing to the high risk status follows the detailed principles addressed under the relevant individual conditions throughout this Atlas, delivered through coordinated, specialist multidisciplinary care.
• Communicate clearly with the woman and her family throughout pregnancy about her risk profile and the resulting individualised care plan.
• Provide psychological support addressing the potentially significant anxiety associated with a high risk pregnancy designation.