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Does no morning sickness mean a boy?

Morning sickness, or nausea and vomiting during pregnancy, affects up to 70-80% of pregnant women. It usually begins around 6 weeks of pregnancy and tends to peak around week 9. Many women wonder if the severity of their morning sickness is related to the sex of their baby.

Does no morning sickness mean you’re having a boy?

There are a few theories on why some women have no morning sickness and whether it’s related to the baby’s sex:

  • Hormone levels – Women carrying boys tend to have higher hCG levels. Since hCG levels are associated with nausea and vomiting, some believe higher hCG = worse morning sickness.
  • Previous pregnancy history – Women who did not have morning sickness in a previous pregnancy are less likely to experience it in subsequent pregnancies, regardless of the baby’s sex.
  • Maternal metabolism – Some studies show moms of boys have higher metabolic rates, which may reduce pregnancy side effects.
  • Fetal development – Male fetuses develop faster in early pregnancy. The rapid growth may be related to less morning sickness.

While these theories suggest less morning sickness could mean you’re having a boy, the link is inconclusive. Many moms carrying boys still have severe morning sickness. Likewise, plenty of women carrying girls have no nausea at all.

Studies investigating the link

Here are some key research findings on the association between morning sickness and fetal sex:

  • A 2006 study published in the Journal of Reproductive Medicine found women with hyperemesis gravidarum (severe nausea and vomiting requiring hospitalization) were 3.5 times more likely to be carrying girls. This suggests morning sickness may be worse with female fetuses.
  • A 2010 study followed over 2,000 pregnant women and found no link between the baby’s sex and the severity of nausea and vomiting symptoms.
  • A 2016 study in the Journal of Perinatal Medicine looked at over 800,000 births in Sweden. They found women carrying boys were less likely to be hospitalized for hyperemesis gravidarum.
  • A 2019 study in the Journal of Maternal-Fetal and Neonatal Medicine found women carrying male fetuses had lower hCG levels and less severe nausea/vomiting than those carrying girls.

As you can see, the findings are mixed. While some studies suggest less morning sickness points to a boy, others find no relationship between morning sickness severity and fetal sex.

Other factors influencing morning sickness

While fetal sex may play a small role, other factors have a bigger impact on morning sickness, such as:

  • Genetics – Family history and genetic factors make some women more susceptible.
  • Hormones – Rapidly rising hCG and estrogen levels cause nausea/vomiting.
  • Stress – Increased cortisol and adrenaline can worsen symptoms.
  • Smell/taste sensitivity – Enhanced senses make smells/tastes more bothersome.
  • GI changes – Slower digestion and gastric emptying trigger nausea.
  • Previous pregnancy – Women who’ve been pregnant before commonly have less morning sickness.
  • Multiple gestation – Carrying twins or higher multiples increases morning sickness.

The severity of nausea and vomiting is likely due to your unique biochemistry and pregnancy circumstances. While carrying a boy may play a small role, it’s not a definitive predictor.

Tips to relieve morning sickness

No matter what sex your baby is, here are some tips to minimize unpleasant morning sickness symptoms:

  • Eat small, frequent meals instead of large ones.
  • Avoid having an empty stomach – keep crackers or other snacks on hand.
  • Stay hydrated by sipping on water, ginger ale, or electrolyte drinks.
  • Get plenty of rest and don’t let yourself get overtired.
  • Avoid nausea triggers like strong smells and spicy, greasy, or acidic foods.
  • Try ginger, peppermint, lemon, or vitamin B-6 to soothe your stomach.
  • Take over-the-counter medicines like Diclegis or Bonjesta to reduce vomiting.
  • Consider acupuncture, acupressure wrist bands or hypnosis if symptoms persist.

Talk to your doctor if morning sickness makes it difficult to stay hydrated and get adequate nutrition. They can provide guidance on managing this unpleasant but common pregnancy symptom.

When morning sickness tends to subside

For most women, nausea and vomiting start to improve around weeks 14-16 of pregnancy as hCG levels plateau. But some continue to experience symptoms well into the second or even third trimester.

Here’s a general timeline for when morning sickness symptoms tend to get better:

  • Weeks 9-12 – Symptoms typically peak around this time, especially upon waking.
  • Weeks 13-16 – Gradual improvement is common as hCG stops rising rapidly.
  • Weeks 16-20 – Most women have significant relief by the end of the 4th month.
  • Weeks 21-delivery – A minority of women still have some lingering nausea.

While general patterns exist, every woman is different. The severity and duration of your morning sickness depends on your unique pregnancy circumstances. Stay in touch with your healthcare provider if vomiting is making it difficult to function.

When to see a doctor

Contact your doctor or midwife right away if you experience any of the following:

  • You cannot keep any food or liquids down for 24 hours
  • You pass only small amounts of concentrated urine or go 8 hours without urinating
  • You feel dizzy or faint when standing up
  • You have dark urine, infrequent urination, or ketones in your urine
  • You have abdominal pain, fever, headache, or stiff neck
  • You’ve lost more than 2-3 pounds or are unable to gain weight
  • You’ve experienced vomiting that is projectile or sporadic throughout pregnancy
  • Your vomit smells like fecal matter or contains blood/bile
  • You’ve experienced nausea/vomiting beyond 20 weeks gestation

Severe dehydration, electrolyte imbalance, and nutritional deficits can happen if severe morning sickness goes unchecked. Seeking prompt treatment is important for the health of both you and your baby.


Experiencing little to no morning sickness does seem to be slightly more common in moms pregnant with boys. However, plenty of women carrying girls also sail through their first trimester nausea-free. Likewise, many with boys still grapple with persistent morning sickness.

The connection between morning sickness severity and fetal sex is inconclusive. While human studies show mixed results, larger analyses do suggest a trend toward less morning sickness with male babies. Even so, it’s just one of many factors influencing nausea and vomiting during pregnancy.

The extent of morning sickness is ultimately tied to your body’s unique response to hormonal and physiologic changes. While preparing for a boy or girl is fun, don’t read into your symptoms too much. The best predictors of your baby’s sex are ultrasound and genetic testing.

Regardless of your baby’s gender, work closely with your healthcare provider if morning sickness makes it difficult to stay nourished and hydrated. There are many effective treatment options available to help you feel your best.

Study Findings
Journal of Reproductive Medicine, 2006 Women with severe morning sickness were 3.5x more likely to be carrying girls
Study of 2,000+ women, 2010 No link found between morning sickness severity and fetal sex
Journal of Perinatal Medicine, 2016 Women carrying boys less likely to be hospitalized for morning sickness
Journal of Maternal-Fetal Medicine, 2019 Women with boys had less severe nausea and lower hCG levels

Summary of morning sickness timeline

Here’s an overview of when morning sickness symptoms typically start to improve for most women:

  • Weeks 9-12: Symptoms peak, especially upon waking
  • Weeks 13-16: Gradual improvement as hCG levels plateau
  • Weeks 16-20: Significant relief by the end of the 4th month
  • Weeks 21-delivery: Some lingering nausea possible

Keep in close contact with your healthcare provider if nausea/vomiting makes functioning difficult or leads to dehydration. With proper treatment, you can minimize symptoms and enjoy a healthy pregnancy.