CORRESPONDENCE

Regarding a call to action on the prevention of fetal alcohol spectrum disorder

To the Editor: We refer to the recent comments by Patel etal.^[1] on the prevention of fetal alcohol syndrome (FAS), and the need for a guideline for the prevention and management of this major problem.^[2] We appreciate their concern about FAS and their serious desire to address it. However, drinking during pregnancy should not be addressed in isolation, as the adverse effects go hand in hand with those of cigarette smoking and the use of other recreational drugs. The Safe Passage Study (SPS)^[3] investigated the effects of drinking and smoking on the outcome of pregnancy in a large international prospective study on pregnant women, including in Cape Town, South Africa (SA).^[3]

In the study of 11 663 pregnancies, the risk of stillbirth was almost twice as high when women smoked, but almost four times higher when they both drank and smoked.^[4] In a study of 11 892 pregnancies, drinking by the mother during pregnancy did not increase the risk of an infant death from a known cause, in contrast with smoking, where the risk increased almost three times. Drinking did not increase the risk of sudden infant death syndrome (SIDS), but smoking increased the risk more than six times, and concomitant use almost 15 times.^[5]

As increased impedance to flow in the uterine and umbilical arteries during early pregnancy are reliable indicators of maternal vascular underperfusion (placental insufficiency), we examined the Doppler flow velocity waveforms in these vessels in 5 806 pregnancies from the SA arm of the SPS, which demonstrated that impedance to flow in the uterine artery was significantly higher when women were heavy drinkers and smokers. Impedance in the umbilical artery was significantly higher even in mild drinkers and smokers. In contrast, neither drinking only nor smoking only had any significant effect on impedance to flow.^[6]

Placental abruption was the most common cause of stillbirth in the SPS.^[4] Further analyses of the 5 806 pregnancies in the SA arm demonstrated that the prevalence of early placental abruption was 0.11% in the 875 women who did not drink or smoke, but 1.25% in the 2 804 women who had used the two substances mildly, another indication of the synergistic effect of concomitant drinking and smoking on pregnancy outcome.^[6]

Exposure to various recreational drugs further jeopardises pregnancy, as reflected by their effects on birthweight z-scores (Fig. 1).^[7]

Birthweight z-scores were significantly lower when women drank and smoked when compared with those who either drank only or smoked only. In addition, the lowest birthweight z-scores were seen in newborns where the mothers smoked marijuana and cigarettes, or used both substances and were also drinking.

In conclusion, as there seems to be a synergistic effect between drinking and smoking in many outcomes, it is likely that smoking may influence development of FAS, and in particular, cognitive aspects of FAS disorders. Prevention programmes on drinking should therefore also address cigarette smoking and the use of drugs in pregnancy in a comprehensive programme.

H J Odendaal

Emeritus Professor of Obstetrics and Gynaecology, Stellenbosch University Cape Town, South Africa

hjo@sun.ac.za

H C Kinney

Emeritus Professor of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, USA

References

1. Patel F, Pittrof R, Naidoo N, Lebese V, MuJlick S. Where is the South African prevention of fetal alcohol spectrum disorder programme? A call to action. S Afr Med J 2025;115(10):e3278. https://doi.org/10.7196/SAMJ.2025.vll5il0.3278        [ Links ]

2. Adebiyi BO, Mukumbang FC, Beytell AM. A guideline for the prevention and management of Fetal Alcohol Spectrum Disorder in South Africa. BMC Health Serv Res 2019;19(1):809. https://doi.org/10.1186/s12913-019-4677-x        [ Links ]

3. Dukes KA, Burd L, Elliott AJ, et al., for the PASS Research Network. The safe passage study: design, methods, recruitment, and follow-up approach. Paediatr Perinat Epidemiol 2014;28(5):455-465. https://doi.org/10.1111/ppe.12136        [ Links ]

4. Odendaal H, Dukes KA, Elliott AJ, et al., for the Prenatal Alcohol in SIDS and Stillbirth (PASS) Network. Association of prenatal exposure to maternal drinking and smoking with the risk of stillbirth. JAMA Netw Open 2021;4(8):e2121726. https://doi.org/10.1001/jamanetworkopen.2021.21726        [ Links ]

5. Elliott AJ, Kinney HC, Haynes RL, et al. Concurrent prenatal drinking and smoking increases risk for SIDS: Safe Passage Study report. EClinicalMedicine 2020;19:100247. https://doi.org/10.1016/j.eclinm.2019.100247        [ Links ]

6. Odendaal H, Wright C, Schubert P, et al. Associations of maternal smoking and drinking with fetal growth and placental abruption. Eur J Obstet Gynecol Reprod Biol 2020;253:95-102. https://doi.org/10.1016/j.ejogrb.2020.07.018        [ Links ]

7. Brink LT, Springer PE, Nel DG, Potter MD, Odendaal HJ. The tragedy of smoking, alcohol, and multiple substance use during pregnancy. S Afr Med J 2022;112(8):526-538. https://doi.org/10.7196/SAMJ.2022.v112i8.16480        [ Links ]