By BSc, MSc (embryologist).
Last Update: 01/15/2019

Even though popular belief says that pregnancies last 9 months, actually it is 10 months. The rationale for this is that, from the medical viewpoint, gestational age is counted from the date of the last menstrual period (LMP). This adds about 2 more weeks to the total length of pregnancy, since ovulation and fertilization occur two weeks after the LMP.

Although the average duration of a full-term pregnancy is 40 weeks, which equals 10 months approximately, labor typically occurs anywhere between weeks 37 and 42.

The reason why pregnancies are monitored weekly is because it allows for a more accurate follow-up. Given that fetal development is constant while pregnant, examining it in small time periods is more useful.

Care for the mother

At this advanced stage of pregnancy, if you have not done it yet, you should practice breathing exercises, as well as exercises to strengthen your pelvic floor muscles. Both will help you during labor.

For example, Kegel exercises are highly recommended during the tenth month of pregnancy. Learn more: What Are Kegel Exercises?

Physically, the symptoms that you may feel are almost the same as the ones you had in previous weeks, including:

  • Back pain
  • Tiredness and fatigue
  • Swollen legs and feet
  • Contractions

Fortunately, digestive and breathing problems tend to improve in month 10. Given that the baby has already entered the pelvis, the level of pressure over the breastbone and the stomach decreases. However, the baby adds more pressure over the bladder, causing you to urinate more frequently.

Normally, at this point of pregnancy you may have started your maternity leave. We recommend that you try to rest as much as possible as well as enjoy relaxation moments, especially during the weeks prior to childbirth.

Also, you are strongly recommended to control your diet strictly during these final weeks. Otherwise, an excessive weight gain can cause problems during and after labor.

Experts recommend a fiber-rich diet, adding supplements of vitamins and folic acid.

You may have gained between 10 to 14 kg during your pregnancy, although each woman and pregnancy is different. Almost half the additional weight is due to the baby, amniotic fluid, and the placenta.

The baby is ready to come out

During this final month of pregnancy, the baby is about 49-53 cm long. As for the weight, it can range between 2.5 kg and 3 kg.

It is likely that he or she has already settled into a head down position and entered the pelvis. Through ultrasound scan, the OB/GYN can determine the real position of the baby. In case he or she is not positioned head-down, your doctor may schedule a C-section.

The digestive system has accumulated a great amount of meconium inside the colon. This substance forms out of the amniotic fluid that the baby swallows during pregnancy, along with other substances like floating waste, cellular waste, and lanugo. It will be the “first poo” of the newborn.

If the sac breaks and the water expelled have a yellowish and/or greenish color, you must go to the hospital at once, since it is a sign that the uterus contains meconium.

The baby has the head full of hair as well as eyebrows. The fingernails seem to surpass the fingertips, and the skin is fully smooth and pinkish.

Vital organs work autonomously, allow him/her to survive without problem outside the uterus. Even the lungs are fully-functioning even though lung development happens very late during pregnancy.

To date, the mechanisms that induce labor naturally are still unknown. However, there is proof that the lungs play a major role during childbirth.

The lungs, when they finish their development, release a substance into amniotic fluid that causes the placenta to alter its hormone levels. Progesterone levels decrease. Simultaneously, the levels of oxytocin, the hormone that regulates uterine contractions, increase.

As one shall see, this is the reason why the lungs become fully-functioning so late in pregnancy: because they are responsible for the start of labor to a large extent.

Month 10 week by week

This stage of pregnancy is probably the most intense of all. You may get into labor literally at any time, and you should be prepared for that. These are the most important events that take place during this month by week:

Week 37

You might notice that fetal movement decreases. This is normal at this stage of pregnancy and is due to:

  • Shortage of room in your belly
  • Loss of amniotic fluid
  • He/she has dropped down into the pelvis

The lanugo covering his body has disappeared except for the shoulders and the upper part of the arms.

Learn more about lanugo and its function in the following article: What Is Lanugo & What Is the Purpose of It?

Week 38

Your baby might rehearse some breathing movements, although he still lacks air in the lungs. He is able to swallow and ingest amniotic fluid perfectly. This makes his digestive system start working.

In case labor has not happened yet, you will have to visit your doctor for fetal heart rate monitoring (FHR) using a series of monitoring devices including latex-free fetal monitoring abdominal belts. FHR is a process used to check the condition of your baby and, in case any anomaly is detected, induce labor.

Electronic fetal heart rate monitoring is commonly done once a week until birth or until labor symptoms start.

Week 39

At week 39 of pregnancy, the cervix is preparing for labor, so is is likely that you notice a mucus-like vaginal discharge.

Also, the increased intensity of Braxton-Hicks contractions can cause a false labor.

Since your waters may break at any moment, you are strongly recommended to avoid long journeys and have your hospital bag already packed.

Week 40

If it hasn’t happened yet, birth is likely to take place during this week.

If birth has not taken place during week 42, the doctors will have to induce it. A longer pregnancy can cause problems, both for the baby and the mother.

Now more than ever, it is crucial that you stay calm. However, it is normal if you are afraid of what’s coming or feel anxious wondering how will your delivery be, especially in first-time moms. The most important is to stay positive and excited during a unique moment in your life.

Signs of labor

All pregnant women must learn to distinguish between real contractions and false labor. The following signs will help you:

Increase in frequency of contractions
Feeling a series of annoying symptoms that resemble birth contractions is normal from the 6th month onwards. Nonetheless, if they become too painful and you have them every 5 minutes, it indicates that the baby is on his way.
Loss of mucus plug
Although losing the mucus plus is not a clear sign that birth has started, it is an indicator that your water is about to break at any time. This jelly-like substance is commonly accompanied by blood clots.
Rupture of membranes
Also known as water breaking, it is a clear sign of labor. Even if you do not have too uncomfortable symptoms, you must go to the hospital after this even at once, since labor can start within the next 24 hours.

FAQs from users

Is it normal to feel very uncomfortable during week 37 of pregnancy?

By Victoria Moliner BSc, MSc (embryologist).

Yes, having annoying symptoms is normal at this stage of pregnancy, not only because labor is getting closer, but because the pregnancy itself is becoming very uncomfortable.

It is normal if you feel pressure and pain in the pelvic area and the vagina due to the descent of the fetus to the birth canal. Nonetheless, in case you have very abnormal symptoms, or if pain is unbearable, you should visit your doctor as soon as possible.

What is a post-term or prolonged pregnancy?

By Victoria Moliner BSc, MSc (embryologist).

A prolonged or post-term pregnancy is a pregnancy that lasts longer than 42 weeks. The main risks include:

Aging of the placenta
If the placenta becomes too old, the supply of nutrients and oxygen to the baby decreases, which can affect his health severely.
Neonatal aspiration of meconium
If the pregnancy lasts too long, the baby may expel the meconium to the amniotic fluid. As a consequence, it can end up entering his lungs, which can cause inflammation of the fetal lungs. This is the reason why you should pay special attention to the color and consistency of your water in case of membrane rupture.
Fetal macrosomia
If the baby is too large, vaginal delivery might not be possible, forcing the doctor to schedule a C-section.

Can you induce labor naturally?

By Victoria Moliner BSc, MSc (embryologist).

Inducing labor is totally unadvisable unless medically indicated. Even if you are more than 40 weeks pregnant and your baby is still in your belly, you have to let your pregnancy continue unless otherwise determined by your doctor. However, in post-term or prolonged pregnancies, labor is typically induced to prevent problems in the baby and/or the mother.

Suggested for you

Week 37 of pregnancy marks the beginning of the last month of pregnancy. The baby, who is now fully formed, can come out at any moment from now on. Learn more about the changes and events to expect during these days here: 37 Weeks Pregnant.

The most important moment of every pregnancy is almost here. For this reason, it is only normal that you are filled with lots of questions and fears. Get more info: Labor & Birth – How Is a Baby Delivered?

When vaginal delivery is not possible, there is no alternative but to schedule a C-section. This surgical procedure allows the birth of babies doing an incision in the abdomen. It is more technically challenging than a vaginal delivery, especially the post-op period. Continue reading here: What Is a C-Section? – Definition & Indications.

Our editors have made great efforts to create this content for you. By sharing this post, you are helping us to keep ourselves motivated to work even harder.

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Authors and contributors

 Victoria Moliner
Victoria Moliner
BSc, MSc
Embryologist
Degree in Biochemistry and Biomedical Sciences from the University of Valencia (UV). Master's Degree in Biotechnology of Human Assisted Reproduction from the UV and the Valencian Infertility Institute (IVI). Presently, she works as a Research Biologist. More information about Victoria Moliner

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