Week 16 of Pregnancy

Week 16 is characterized by many changes in the baby, especially in the nervous system. It’s a unique and unrepeatable stage!
Week 16 of Pregnancy

Last update: 07 August, 2021

Are you already in week 16 of pregnancy? It’s a perfect time to think a little about how your baby and your body are doing! In the following paragraph, you’ll discover how well your baby’s nervous, muscular, renal and skin systems must be developing, which is impressive for their small size.

We’ll also tell you a little about what you may feel during this stage, especially physical and emotional discomfort, something very common in pregnant women. But don’t worry, the idea is to enjoy the process. If you want to know a little more about it, keep reading this article.

Baby’s development in week 16 of pregnancy

Week 16 is a time of major changes.
It’s a time full of changes!

Babies’ growth rate is going from strength to strength! Little by little, they’re approaching the figure of a human being thanks to the development of all their tissues and organs. To give you an idea, if we were to measure babies at this stage from the crown of the head to the buttocks, they would have an average size of 12 centimeters. As for the weight, they would weigh about 80 grams.

Of course, these values tend to change a lot. They depend, to a large extent, on the genetic characteristics of both parents, the specific conditions during pregnancy and the country under consideration. But generally speaking, your baby is about the size of an avocado.

As days go by, their nervous system grows. This is very important, as it’ll allow them to move all their muscles (spontaneously or reflexively), something very necessary to prepare their body for basic actions such as breathing or swallowing. Their skin is covered by a thin layer called lanugo, which acts as a thermal insulator.

Their kidneys, organs specialized in filtering the blood and eliminating toxins, are developing at an accelerated rate. The same happens with the gastrointestinal tract, in the future, these organs will directly influence the amount of amniotic fluid inside of you.

The most common symptoms during this week

While your baby is developing at an accelerated pace and will slowly start to move around, it may still be too early to start feeling that. What you’ll start to notice is a small lump in your lower abdomen, which of course corresponds to your uterus. Little by little, it’ll grow!

As you’re now in the second trimester of pregnancy, the vomiting will probably stop being so frequent. This is due to hormonal changes, and it’s very welcome! However, as there are many organs and blood vessels surrounding the uterus, you may start to experience other things.

Swelling of the lower extremities, as long as it’s mild, is normal. So are backaches in the lower back and even around the sciatic nerve (from the back down the leg). If you experience any of these symptoms, it’s advisable to see a doctor for analgesic treatment.

Frequent mood swings, increased urge to go to the bathroom, insomnia and stress are some possible consequences. You’re probably already quite familiar with all this and it may become a constant. However, you should never neglect medical appointments, communication with your loved ones and, above all, the health of your baby.

Tips and recommendations for week 16 of pregnancy

In week 16, the way you’ve probably been looking after yourself since you found out you’re pregnant should be maintained. This is very important in terms of food and medical check-ups.

The way you eat should be as balanced as possible. Unless you have a major condition that requires specialized recommendations —diabetes mellitus, cardiovascular disease or other similar conditions— your diet should maintain a balanced intake of carbohydrates, lipids and proteins.

The consumption of coffee, sugar, junk food and, in general, ultra-processed industrial products should be reduced as much as possible. The same applies to alcoholic beverages and tobacco, whose effects on the baby can be very marked and harmful.

Have you already planned your regular visit to the doctor? Regardless of whether your pregnancy is monitored by a midwife, your obstetrician’s appointments should be on time. The obstetrician will indicate the corresponding tests according to your particular case, which may vary depending on your previous prenatal check-up.

The most frequent laboratory tests include a complete blood count, blood sugar levels (glycemia), coagulation studies… In addition, the typical ultrasound can’t be missing. Even if it’s not always performed during this week, depending on what the doctor tells you, it’s likely to perform it at this stage.

Frequently asked questions

We’ve selected two of the most frequently asked questions that mothers often have at this stage.

1. Can I know the baby’s sex at this stage?

An ultrasound can be done in week 16.
An ultrasound is necessary, but it’s still too early!

In the vast majority of cases, it’s not possible. The genitalia aren’t yet fully visible on an ultrasound, so knowing how to tell the difference between a boy and a girl is complicated. But don’t despair, because you’ll be able to tell between the 17th and 20th week, depending on your case. A good idea is to prepare the gender reveal!

2. Is urinary discomfort normal in week 16 of pregnancy?

Even if we’ve mentioned that the increased frequency with which you go to the bathroom is normal, you should be very attentive to other symptoms. If you feel itching, burning or pain when you urinate, it’s very likely that you’re developing a urinary tract infection. And if you have a fever or a lot of lower back pain, even more so.

The best thing to do is to see your doctor as soon as possible to treat the problem. Most likely, after a few basic tests, you’ll receive a treatment based on oral antibiotics.

A week to remember

As you may have noticed, this isn’t just any week. Your baby is growing at an accelerated pace and you’ll feel the effects on your body. The most important thing is to enjoy the process and remember that moments like this never come back.

All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Carrascosa A. Crecimiento intrauterino: factores reguladores. Retraso de crecimiento intrauterino. An Pediatr 2003;58(Supl 2):55-73.

This text is provided for informational purposes only and does not replace consultation with a professional. If in doubt, consult your specialist.