Preventative therapy for malaria has positive effect on baby birth weight, unless intestinal pathogens are present

June 29, 2022

Malaria in pregnancy (MiP) is a major public health problem with substantial risks for mothers and their babies. The combination treatment sulfadoxine-pyrimethamine (SP), given for intermittent preventive therapy of malaria in pregnancy (IPTp), is one of the few existing interventions that improve outcomes for both mother and baby, despite widespread SP-resistant malaria.

Origins of the study

r. Andreea Waltmann (left) smiles with the late Dr. Steve Meshnick.

A study conceptualized by the late Steve Meshnick, MD, PhD, professor of epidemiology at the UNC Gillings School of Global Public Health and member of the UNC Institute for Global Health and Infectious Diseases (IGHID) — who partnered with the Centers for Disease Control and Prevention to make it a reality — examined how the beneficial effects of SP on baby birth weight might arise from SP activity on mothers, such as maternal weight gain during pregnancy.Postdoctoral IGHID scholar Andreea Waltmann, PhD, with IDEEL, conducted the work under Meshnick’s mentorship. She describes why the study — published in eBioMedicine — is highly significant for public health, adding that malaria in pregnancy was a field of research dear to Meshnick’s heart.

“SP-resistant malaria parasites are now common, bringing into question whether SP therapy in pregnancy should be discontinued,” Waltmann said. “Paradoxically, SP’s positive effects of reducing maternal anemia and improving baby birth weight have not diminished, even in areas with high rates of SP-resistant malaria parasites.”

“Our study is the first step in elucidating that the observed benefits of SP on pregnant women and their babies come from the promotion of maternal weight gain during the second and third trimesters of pregnancy. In addition, our results indicate that this positive weight gain effect is lessened if intestinal pathogens are detected in the mother’s stool prior to IPTp initiation, which in turn may negatively influence birth weight.”

Recruiting pregnant women

The randomized controlled trial and sub-study recruited pregnant women between 16- and 28-weeks gestational age who were attending their first prenatal care visit at Machinga District Hospital in Malawi. Study participants received a monthly preventative treatment of either sulfadoxine-pyrimethamine (SP) or dihydroartemisinin-piperaquine (DP). In addition to measuring body weights, the sub-study collected monthly stool samples and screened them for common intestinal pathogens. Women with high-risk pregnancies or other medical conditions were excluded.

Findings showed treatment with SP was consistently associated with higher nutritional indicators, such as body-mass index and gestational weight gain. The presence of maternal intestinal pathogens before treatment, however, lessened this effect. Overall, the study indicated SP therapy during pregnancy has additional, malaria-independent benefits to both mother and baby via the promotion of weight gain. Preventing common gut pathogens in the mother may be an additional intervention opportunity for optimal pregnancy weight gain and baby birth weight.

“Further studies are needed to confirm the generalizability of these findings outside of Malawi, but they do offer an innovative and exciting perspective on how we may be able to intervene during the prenatal period to ensure the health of both mother and baby, since a newborn’s ability to thrive is closely linked to maternal health,” explained Waltmann.

“While we didn’t get a chance to publish this paper before Dr. Meshnick’s untimely passing, I remember how excited he was when I shared with him the results of my analysis, which unexpectedly — and for the first time in our field — showed that SP has a positive effect on baby birth weight by promoting the mother’s weight gain during pregnancy,” she added. “I hope that if he were still with us, he’d feel as proud of this paper as I do.”

The study team also included: Elizabeth T. Rogawski McQuade; Jobiba Chinkhumba; Darwin J.Operario; Enala Mzembe; Megumi Itoh; Michael Kayange; Sydney M. Puerto-Meredith; Don P. Mathanga; Jonathan J. Juliano; Ian Carroll; and Luther A. Bartelt.

Contact the UNC Gillings School of Global Public Health communications team at sphcomm@unc.edu.