Congenital anomalies and associated risk factors in a Saudi population: a cohort study from pregnancy to age 2 years

Abstract

Objective: To assess the three key issues for congenital anomalies (CAs) prevention and care, namely, CA prevalence, risk factor prevalence and survival, in a longitudinal cohort in Riyadh, Saudi Arabia.

Setting: Tertiary care centre, Riyadh, Saudi Arabia.

Participants: Saudi women enrolled during pregnancy over 3 years and their 28 646 eligible pregnancy outcomes (births, stillbirths and elective terminations of pregnancy for foetal anomalies). The nested case-control study evaluated the CA risk factor profile of the underlying cohort. All CA cases (1179) and unaffected controls (1262) were followed through age 2 years. Referred mothers because of foetal anomaly and mothers who delivered outside the study centre and their pregnancy outcome were excluded.

Primary outcome measures: Prevalence and pattern of major CAs, frequency of CA-related risk factors and survival through age 2 years.

Results: The birth prevalence of CAs was 412/10 000 births (95% CI 388.6 to 434.9), driven mainly by congenital heart disease (148 per 10 000) (95% CI 134 to 162), renal malformations (113, 95% CI 110 to 125), neural tube defects (19, 95% CI 25.3 to 38.3) and chromosomal anomalies (27, 95% CI 21 to 33). In this study, the burden of potentially modifiable risk factors included high rates of diabetes (7.3%, OR 1.98, 95% CI 1.04 to 2.12), maternal age >40 years (7.0%, OR 2.1, 95% CI 1.35 to 3.3), consanguinity (54.5%, OR 1.5, 95% CI 1.28 to 1.81). The mortality for live births with CAs at 2 years of age was 15.8%.

Conclusions: This study documented specific opportunities to improve primary prevention and care. Specifically, folic acid fortification (the neural tube defect prevalence was >3 times that theoretically achievable by optimal fortification), preconception diabetes screening and consanguinity-related counselling could have significant and broad health benefits in this cohort and arguably in the larger Saudi population.

Keywords: congenital anomalies; outcome; prevalence; prevention; risk factors.

Figure 1

Catchment site and the study flow chart. Case catchment areas (A to E). A, antenatal clinic; B, at birth; C, the “one-month clinic”; D, geneticist “one-month clinic” and E, other areas. 1, 2, 3 are postnatal, stillbirth and antenatal respectively. AN, antenatal; BD, birth defect; PN, postnatal; SB, stillbirth.

Figure 2

Study population and distribution of pregnancies and their outcomes. PSMMC, Prince Sultan Military Medical City; ETOPFA, elective terminations of pregnancy for foetal anomalies. †Eight control foetuses were stillbirth.

Figure 3

Frequency among control subjects of selected risk factors for CA. *Frequency of prior child with BD computed among non-primiparous women. BD, birth defect; BMI, pre-pregnancy maternal body mass index; CAs, congenital anomalies.