Bariatric surgery and conception timing: maternal and neonatal outcomes

Renata Barbosa; da Silva Beatriz Tavares; Susana Garrido; Ariana Maia; Liliana Fonseca; Joana Vilaverde; Pereira Maria Teresa; Diana Martins; Fernando Pichel; Jorge Dores

doi:10.1530/endoabs.110.EP878

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Endocrine Abstracts (2025) 110 EP878 | DOI: 10.1530/endoabs.110.EP878

ECEESPE2025 ePoster Presentations Metabolism, Nutrition and Obesity (164 abstracts)

Bariatric surgery and conception timing: maternal and neonatal outcomes

Renata Barbosa ¹ , Beatriz Tavares da Silva ¹ , Susana Garrido ¹ , Ariana Maia ¹ , Liliana Fonseca ¹ , Joana Vilaverde ¹ , Maria Teresa Pereira ¹ , Diana Martins ² , Fernando Pichel ³ & Jorge Dores ¹

Author affiliations

¹Endocrinology Department, Centro Hospitalar e Universita´rio de Santo António, ULS Santo António, Porto, Portugal; ²Obstetrics and Gynaecology Department, Centro Materno-Infantil do Norte Albino Aroso, ULS Santo António, Porto, Portugal; ³Department of Nutrition, Centro Hospitalar e Universita´rio de Santo António, ULS Santo António, Porto, Portugal

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Introduction: The recommended interval between bariatric surgery and conception varies, generally ranging from 12 to 24 months. Some studies associate conception within two years post-surgery with an increased risk of preterm delivery, neonatal intensive care unit(NICU) admission, and small-for-gestational-age(SGA) newborns. However, other studies show no significant differences.

Objective: To evaluate the impact of the interval between bariatric surgery and conception (“early conception”, ≤12 months vs “late conception”, >12 months) on pregnancy outcomes.

Materials and Methods: A retrospective study was conducted on pregnancies following bariatric surgery at a Portuguese tertiary center. Maternal and neonatal complications were compared between two groups based on surgery-to-conception interval. Composite maternal complications included preeclampsia, polyhydramnios, and miscarriages, while composite fetal complications encompassed preterm births, need for phototherapy, and admission to the NICU. Statistical analyses were performed using IBM SPSS Statistics.

Results: The study included 102 pregnancies (92 women) between 2015 and 2023. The median maternal age was 34 years (23-45). Most patients underwent gastric bypass (66.7%, n = 68), while 33.3% (n = 34) had sleeve gastrectomy. The median surgery-to-conception interval was 34 months, with 22.5% (n = 23) conceiving within 12 months post-surgery. The median gestational age at delivery was 39 weeks (23-41), and the median birth weight was 3030g (1000-4140g). The cesarean section rate was 33.0%. Pregnancy complications included 12 cases (12.2%) of preeclampsia, 2 cases (2.1%) of polyhydramnios, 3 miscarriages (3.1%) and 15 preterm births (15.6%). Neonatal outcomes included 20 large-for-gestational-age newborns (20.8%), 11 SGA (11.5%) and 11 congenital malformations (11.5%). Additionally, 28(29.2%) required phototherapy, and 9(9.4%) were admitted to the NICU. No statistically significant differences were found between groups in terms of maternal-fetal complications, whether analyzed individually or as composite outcomes(Table 1).

Table 1. Pregnancy outcomes in early vs late conception group
	Early conception (n = 23)	Late conception (n = 79)	p-value
Cesarean section(n, %)	7(33.3)	25(32.9)	0.970
Preeclampsia(n, %)	1(4.8)	11(14.3)	0.452
Polyhydramnios(n, %)	1(5.0)	1(1.3)	0.378
Miscarriages(n, %)	2(9.5)	1(1.3)	0.120
Preterm births(n, %)	1(5.0)	14(18.4)	0.183
Large-for-gestational-age(n, %)	4(20.0)	16(21.1)	0.918
SGA(n, %)	1(5.0)	10(13.2)	0.449
Congenital malformations(n, %)	1(5.0)	10(13.2)	0.449
Need for phototherapy(n, %)	8(40.0)	20(26.3)	0.273
Admission to the NICU(n, %)	0(0)	9(11.8)	--
Maternal complications(n, %)	4(19.0)	13(17.6)	0.876
Fetal complications(n, %)	9(45.0)	31(40.8)	0.801

Conclusion: While current guidelines recommend delaying conception, our findings suggest that pregnancy within one-year post-surgery may be safe. However, the small sample size may have limited the ability to detect significant differences, highlighting the need for further studies.