Week 33 Pregnancy: Hormones, Feeling Sick & Baby Born at 33 Weeks (2023)

You’ve made it to week 33 of your pregnancy (31 weeks from conception.) You will be holding your baby before you know it! Let’s check in on how you and baby are growing, talk about symptoms you may be feeling, and learn about what it would be like if baby were to be born this week.

Estimated reading time: 7 minutes

Updated August 29, 2021

Week 33 Pregnancy: How Big is Baby?

Your baby continues to gain weight quickly. He’s gaining about 1/2 pound a week as he gets ready for birth. He now weighs in at around 4 1/4 pounds. He’s about 12 inches long from crown to rump, or 17 1/4 inches from crown to heel (1). If you wanted to make one of the fruit comparisons that are always a fun way to get a visual, your baby is a sweet little pineapple!

What else can we learn about your cute, tiny one?

• He closes his eyes when asleep and opens them when awake.
• His pupils react to light.
• He drinks up to a pint of amniotic fluid a day. This is practice for his gastrointestinal system.
• You likely have more baby than amniotic fluid now, making his movements feel stronger and sharper (2).

Baby Bump

Your bump continues to grow steadily, right along with your baby. You can now feel the top of your uterus about 5 1/4 inches above your belly button. When your doctor or midwife measures the fundal height — the distance from pubic symphysis to fundus — it’s now about 13 1/4 inches.

If your pre-pregnancy weight was in the range of normal, and if you’ve gained the recommended amount along the way, you’ve probably gained between 20 and 27 pounds. You’ll continue to gain a pound or two a week until baby is born. Your weight gain may be a little more or less depending on your specific situation, whether you came into your pregnancy overweight or underweight, and what your doctor or midwife advised.

Week 33 Pregnancy: Symptoms

Hormones

Progesterone, Estrogen, Oxytocin, Relaxin

We’ve talked about hormones throughout your entire pregnancy, as they are responsible for, or at least have a hand in, nearly every symptom you experience. You’re currently right at the point where estrogen and progesterone are at their highest. Estrogen levels are now six times what they were before your pregnancy!

All the hormones that have worked together to change your body and support your baby will soon begin shifting to prepare for the onset of labor. Near the time labor starts, progesterone will drop, oxytocin levels will rise to produce contractions, and relaxin will also increase to loosen ligaments and help relax the cervix.

Emotional Rollercoaster

Hormone changes can make you feel like you’re on an emotional roller coaster. This is especially true when those hormones are paired with exhaustion, lack of sleep, and fears and excitement about huge life changes. Eat healthy foods, drink plenty of water, and take time to rest, relax, and recharge as often as you can; these things will help with some of the non-hormone components of the emotional rollercoaster. As for the hormones, you’ll just have to hold on and ride it out. Be gentle with yourself. Sometimes just recognizing that there’s a reason behind your emotions makes them easier to cope with.

If you are really struggling with Pregnancy Depression, Anxiety, or Stress, you’re not alone. Talk to your doctor or midwife. These are common, and your caregiver has helped many pregnant women through them.

Braxton Hicks Contractions

You may not experience them yet, but your body may start practicing for labor by having Braxton Hicks contractions. These “practice” contractions don’t mean that you’re in labor, and don’t cause any cervical changes. What you’ll notice is just a tightening in your bump that lasts 20 – 30 seconds and then returns to relaxed. They don’t come in any particular pattern, but may be more frequent after physical activity or sexual activity. Changing positions or activity levels usually stops them.

If your contractions are longer or come at regular intervals, or if you have any concerns that you may be in labor, err on the side of caution and give your provider a call.

Nausea

You probably hoped you were done with nausea when morning sickness passed, but may have discovered that you’re feeling sick again. Nausea and heartburn are not unusual, and in fact, some women even lose a few pounds right at the end of their pregnancies (4). As with almost every symptom we’ve discussed, changing hormones may play a role. The other factor is that your baby has grown so much that your stomach is running out of room. Eating, even smaller amounts than you’re used to, may make you feel overfull and uncomfortable.

You may find that it helps to eat multiple smaller meals throughout the day rather than three larger ones. Just be sure that you are eating regularly. Having an empty stomach can make both nausea and heartburn worse. Even more importantly, both you and baby need the energy for the coming stress of labor and birth.

What if Baby is Born at 33 Weeks?

If you were to deliver your baby now, you would likely be scared and worried and overwhelmed. All of those feelings are understandable. However, the great news is that a baby born at 33 weeks gestation has a great chance of not only surviving, but doing so without long-term complications. Premature babies born at 33 weeks are considered moderately preterm. They will likely have only a short NICU (Neonatal Intensive Care Unit) stay and few complications (5).

Still, the hope is that baby stays in for at least another month or so. If you were to experience preterm labor, your doctor would likely try to postpone baby’s birth. They can’t necessarily stop labor altogether, but there are medications they can use to slow it down. Meanwhile, they can give your baby medications that help speed up lung development so that he is born as healthy as possible (6). Buying even a few extra days can be beneficial.

Prematurity

If your baby were to arrive early, the main concerns would be:

• Immature lungs. Baby may need a little help with breathing at first.
• Body temperature regulation. Baby may need to spend some time in a temperature-controlled isolette until she is able to maintain her own body temperature.
• Feeding. A preterm baby sucks weakly and her swallow and gag reflexes are unreliable. Eating on her own and gaining weight is usually the last hurdle a premature baby overcomes before being discharged from the hospital.

You can find more great information about premature babies on the March of Dimes website. If you find yourself parenting a premature child, the March of Dimes may be a valuable resource for you.

Come back next week to see what’s happening in your body and your baby’s in week 34!

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Resources:

1. Glade, B.C., Schuler, J. (2011). Your Pregnancy Week by Week, 7th edition. First Da Capo Press.
2. What to Expect. “Watch Your Baby’s Growth at Week 33.” What to Expect, 17 Jan. 2019, www.whattoexpect.com/pregnancy/week-by-week/week-33.aspx.
3. Daley, Kate. “How Pregnancy Hormones Affect Your Body in Each Trimester.”Today’s Parent, 19 Dec. 2018, www.todaysparent.com/pregnancy/pregnancy-health/how-pregnancy-hormones-affect-your-body-in-each-trimester/.
4. The American College of Obstetricians and Gynecologists. (2010). Your Pregnancy and Childbirth Month to Month, 5th edition.
5. Bird, Cheryl. “The Different Stages Premature Babies Can Be Born.”Verywell Family, www.verywellfamily.com/premature-babies-week-by-week-2748606.
6. Simkin, P., Whalley, J., Keppler, A., Durham, J., & Bolding, A. (2018).Pregnancy, childbirth, and the newborn: The complete guide. New York, NY: Da Capo Lifelong.

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