Does Anterior Placenta Position Actually Raise Risk?
Does having an anterior placenta actually raise your risk of pregnancy complications?
Based on the best available evidence, no — an anterior placenta is not treated as a risk factor in standard prenatal care, and it should not change how you're monitored. The largest study on this question, a population-based cohort of 74,087 pregnancies, compared placental positions directly and found that anterior placentas were not the ones associated with adverse outcomes. There are a couple of genuine, narrow exceptions worth knowing about, and there is one placental position that does carry consistent risk — but it isn't the anterior one.
What is an anterior placenta, and how common is it?
An anterior placenta simply means the placenta has implanted on the front wall of the uterus, closest to your abdomen, rather than the back wall (posterior), the top (fundal), or the side (lateral). It's extremely common: in that same 74,087-pregnancy cohort, 47.8% of placentas were anterior and 46.4% were posterior, with fundal and lateral positions making up only a few percent each. In other words, an anterior placenta is very close to a coin flip, and it's identified incidentally at the routine anatomy scan around 18 to 21 weeks.
The main practical difference it makes is that fetal movements may be felt somewhat later or less distinctly, since the placenta cushions some of that sensation, and it can make certain procedures like amniocentesis require more careful needle placement. Neither of those is a complication.
Where does the "anterior placenta increases risk" claim come from?
If you've seen claims online that an anterior placenta raises your risk of gestational diabetes, preeclampsia, placental abruption, or growth restriction, that traces back to a specific study: a retrospective review of 474 case records at a single center, published in 2013. It reported associations between anterior placental position and pregnancy-induced hypertension, gestational diabetes, abruption, growth restriction, and intrauterine fetal death.
That study also reported that placental position was associated with maternal blood type — 54% of women with O-positive blood had anterior placentas, while A-positive was associated with posterior. There's no obvious biological mechanism for a relationship between blood group and which uterine wall an embryo implants on, and findings like that are usually a signal that a dataset is producing correlations that won't hold up elsewhere.
Has anyone tried to replicate it?
Yes — and this is the part that usually gets left out. It would be inaccurate to say the question hasn't been studied since. It has, in much larger populations, and the results do not support the anterior claim.
The Stockholm-Gotland cohort of 74,087 nulliparous women looked at all four placental locations against pregnancy, delivery, and infant outcomes, adjusting for maternal age, height, country of birth, smoking, infant sex, and IVF. Compared with posterior placentas, it was fundal and lateral positions that carried elevated risk — very preterm birth (adjusted OR 1.78 and 2.12), moderate preterm birth, small-for-gestational-age birth (aOR 1.67 and 1.77), and manual removal of the placenta (aOR 3.27 for both). Anterior placentas did not stand out as the risky position in this analysis.
So the more accurate framing isn't "one study said something alarming and nobody checked." It's that larger and better-adjusted studies have checked, and they point somewhere else entirely.
Is there a placental position that does matter?
There is, and it's worth knowing because it's the finding that actually replicates. A 2022 systematic review and meta-analysis pooled 16 studies covering 4,947 pregnancies with a lateral placenta against 96,035 controls. Lateral placental position was associated with preeclampsia (OR 2.92), fetal growth restriction (OR 2.18), small-for-gestational-age neonates (OR 1.74), and preterm delivery (OR 1.65).
That's a meaningfully different situation from the anterior claim: consistent direction across many studies, a large pooled sample, and a plausible mechanism, since a laterally implanted placenta may be supplied primarily by one uterine artery rather than drawing evenly from both. The heterogeneity between studies was high for the preeclampsia estimate, so this isn't a settled number either — but it is a real signal, and it illustrates the difference between a claim that survives replication and one that doesn't.
Are there situations where an anterior placenta does change anything?
Two, and they're worth being precise about rather than glossing over.
Anterior placenta combined with a previous cesarean. This is the genuine clinical exception. If a placenta is low-lying or covering the cervix and sits anteriorly over a prior cesarean scar, the risk of placenta accreta spectrum — where the placenta implants abnormally deeply into the uterine wall — rises substantially. In a prospective population-based study of women with any prior cesarean plus a low-lying placenta or previa, accreta spectrum rates were 9% with a posterior low-lying placenta versus 21% with an anterior low-lying placenta, and 33% with previa. If you've had a cesarean and your placenta is anterior and low, that combination is genuinely worth discussing with your OB. An anterior placenta in a normal position, with no prior uterine surgery, is a different situation entirely.
Labor and delivery, possibly. A prospective study of 2,354 term pregnancies found anterior placental location associated with a higher rate of labor induction, more cesareans for failure to progress, a longer third stage, more manual removal of the placenta, and more postpartum hemorrhage in vaginal births. These are delivery-course findings rather than the pregnancy complications in the viral claim, the mechanism isn't established, and they haven't reshaped clinical practice. But it's more honest to say "anterior position may have some association with how labor unfolds" than to say it means nothing at all.
What actually deserves your attention instead?
The real risk factors for preeclampsia, gestational diabetes, growth restriction, and abruption are well established and don't depend on placental position: chronic hypertension, pre-existing or gestational diabetes, insulin resistance, obesity, autoimmune and thrombophilic conditions, and personal or family history of these complications. These are the factors that actually inform monitoring decisions, and unlike where your placenta happened to implant, several of them are modifiable before and during pregnancy.
Our pieces on what you can still control with a high-risk pregnancy and supporting a partner through gestational diabetes cover these in more depth. And if this article's pattern feels familiar — an ultrasound finding that sounds ominous but usually isn't — our piece on what placental calcification on ultrasound actually means works through a very similar question.
The Bottom Line
An anterior placenta is a normal anatomical variant found in roughly half of pregnancies, and the claim that it independently raises your risk of pregnancy complications comes from a single retrospective study whose findings larger cohorts have not confirmed. The placental position with consistent evidence behind it is lateral, not anterior. The one anterior-specific scenario that genuinely warrants a conversation is an anterior low-lying placenta after a previous cesarean, because of accreta risk — outside of that, anterior position isn't a reason for extra worry or extra monitoring. At our Huntington office, a large part of what we do is helping patients separate genuine, evidence-backed risk factors from online claims that outpace the research, and then focus effort on the factors that are actually modifiable. Our Metabolic & Immune Fertility Evaluation is built around exactly those.
This article is for general educational purposes and isn't a substitute for individualized guidance from your OB-GYN or maternal-fetal medicine specialist. Any concerns about placental position, pregnancy complications, or risk factors should be evaluated directly by your care team.
East to West Fertility is a metabolic and immune-focused fertility clinic in Huntington, Long Island, serving patients across Long Island, NYC, and beyond. Learn more about our Metabolic & Immune Fertility Evaluation or call 631-416-4940.
References:
- Granfors M, et al. "Placental location and pregnancy outcomes in nulliparous women: A population-based cohort study." Acta Obstetricia et Gynecologica Scandinavica, 2019. doi:10.1111/aogs.13578
- "The impact of lateral placenta on preeclampsia and small for gestational age neonates: a systematic review and meta-analysis." Journal of Perinatal Medicine, 2022. doi:10.1515/jpm-2022-0118
- "Risk factors for placenta accreta spectrum disorders in women with any prior cesarean and a placenta previa or low lying: a prospective population-based study." Scientific Reports, 2024. doi:10.1038/s41598-024-56964-9
- Torricelli M, et al. "Anterior placental location influences onset and progress of labor and postpartum outcome." Placenta, 2015. PMID 25573094
- "Association of placental location with pregnancy outcome and neonatal outcome, and its correlation with different blood groups." PMC3935544.
