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Anemia in pregnancy means your blood has too little hemoglobin to carry oxygen well, usually below 11 g/dL in the first and third trimesters. Low iron is the most common cause. Fatigue, dizziness, and pale skin are common signs, though a routine prenatal blood test is a clear way to verify. You and your provider should decide what care fits for you.
Anemia in pregnancy means the hemoglobin concentration in your blood is lower than expected during pregnancy, reducing its oxygen-carrying capacity. In a Lancet Global Health analysis, a team led by Gretchen Stevens estimated that about 36% of pregnant women worldwide were anemic in 2019. If you are pregnant or planning to be, knowing the signs and the numbers helps you have clearer conversations at prenatal visits.
Key takeaways
- Main cause: Low iron is the most common cause because blood volume and your baby’s needs both grow.
- Overlapping signs: Tiredness, pale skin, and shortness of breath can point to anemia but also occur in healthy pregnancies.
- Baby and birth: Anemia early in pregnancy is linked to higher odds of preterm birth and low birth weight.
- Timing: Providers often check hemoglobin a couple of times during pregnancy, so ask when your next blood count is due.
When you are pregnant, what hemoglobin level counts as anemia?
Anemia in pregnancy is defined as hemoglobin below 11 g/dL in the first and third trimesters and below 10.5 g/dL in the second. Hematocrit, also called packed cell volume (PCV), is checked alongside it. Cutoffs can differ slightly by lab, so your provider reads your results in context.
This table lists typical cutoffs, and the figures are estimates that vary by lab.
| Measure | Usual anemia cutoff in pregnancy (estimate) | What it reflects |
|---|---|---|
| Hemoglobin | Below 11 g/dL (first and third trimesters); below 10.5 g/dL (second) | The protein in red blood cells that carries oxygen |
| Hematocrit (PCV) | Below about 33% (first and third); about 32% (second) | The share of your blood made up of red blood cells |
| Red blood cell count | Varies by lab and trimester | Compared with your lab’s range |
What are the signs you might be anemic during pregnancy?
Common signs of anemia are feeling tired or weak, paler skin, a rapid heartbeat, shortness of breath, and trouble concentrating. Many of these also show up in pregnancies without anemia, so symptoms alone cannot tell you. Some people also notice dizziness or cold hands. A blood test gives a clearer picture.
Because low iron can feel like ordinary pregnancy fatigue, jot down when tiredness or dizziness hits and share it with your provider, along with other early pregnancy symptoms.
What causes low iron during pregnancy?
Low iron in pregnancy usually happens because your body needs more of it. As the American Society of Hematology explains, blood volume rises by about 20% to 30%, which raises the iron and vitamins needed to make hemoglobin. Iron also supports your baby and the placenta, so demand can outpace what your diet and stores supply.
Risk goes up with pregnancies close together, twins or more, frequent vomiting, low iron intake, heavy periods before pregnancy, or a history of iron deficiency.
Can anemia in pregnancy affect my baby?
Yes, anemia can affect your baby, especially when it is more severe or starts early. A BMJ systematic review from Harvard researchers linked anemia in the first or second trimester to about 29% higher odds of low birth weight and 21% higher odds of preterm birth.
How do providers check for anemia in pregnancy?
Providers usually start with a complete blood count, a simple blood test, at your first prenatal visit and often again later in pregnancy. If hemoglobin looks low, they may order iron studies, such as ferritin, to see whether low iron is the cause. Your provider then decides whether food changes, iron supplements, or other steps make sense for you.
How can Premom support you before and during pregnancy?
The Premom app gives you one place to build a record for your prenatal visits. Before pregnancy, log period flow across cycles, since heavy periods are a listed risk factor for low iron. Once pregnant, you can log symptoms such as fatigue, dizziness, and headaches to create a record you can discuss at prenatal visits.
For example, fatigue logged on 3/17 and dizziness at 4:01 PM on 3/19 show your provider a pattern quickly.
Premom keeps flow, symptoms, and test results on one timeline.
Key terms explained
Hemoglobin: the protein in red blood cells that carries oxygen to your body and your baby.
Hematocrit: the percentage of your blood made up of red blood cells. It is also called PCV.
Iron deficiency anemia: anemia caused by too little iron to make enough hemoglobin.
Ferritin: a protein that stores iron. Providers may check it to see your iron reserves.
The information provided in this article is for educational and informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare professional or OB-GYN regarding any questions you may have about your menstrual cycle, reproductive health, or medical conditions.
References
- Stevens GA, Paciorek CJ, Flores-Urrutia MC, et al. National, regional, and global estimates of anaemia by severity in women and children for 2000–19: a pooled analysis of population-representative data. Lancet Glob Health. 2022;10(5):e627–e639. doi:10.1016/S2214-109X(22)00084-5
- American College of Obstetricians and Gynecologists, Committee on Practice Bulletins for Obstetrics. Anemia in pregnancy: ACOG Practice Bulletin No. 233. Obstet Gynecol. 2021;138(2):e55–e64. doi:10.1097/AOG.0000000000004477
- American Society of Hematology. Anemia and pregnancy. Accessed September 21, 2026. https://www.hematology.org/education/patients/anemia/pregnancy
- Haider BA, Olofin I, Wang M, Spiegelman D, Ezzati M, Fawzi WW; Nutrition Impact Model Study Group (anaemia). Anaemia, prenatal iron use, and risk of adverse pregnancy outcomes: systematic review and meta-analysis. BMJ. 2013;346:f3443. doi:10.1136/bmj.f3443
