This week marks the halfway point of a full term pregnancy. The fetus now measures between 13.4cm 15.2cm in length (crown to rump) and weighs approximately 200g. The fetus is now covered with a greasy, white, protective substance called vernix caseosa that protects the delicate skin from the amniotic fluid. The vernix is usually shed during the last few weeks of pregnancy, although some babies are born with some vernix remaining.It’s best to rub this into baby’s skin rather than washing it off as it is full of Vitamin K which is needed by babies.
Key developments in the brain will take place during this week. In particular, sensory nerve cells, responsible for sight, hearing, smell, touch and taste are all developing in specialist areas of the brain. The actual production rate of nerve cells is slowing down as existing nerve cells grow and form ever-increasingly complex connections. The fetus now also sleeps and wakes in a regular pattern and is continuing to practice breathing movements in preparation for life outside the uterus.
The fetus continues to swallow amniotic fluid and the kidneys are now effectively producing urine. In addition to this, hair continues to sprout from the scalp.
Your uterus has now grown to the extent that it is level with your belly button. The uterus will continue to grow approximately 1cm per week for the remainder of the pregnancy.
This may be the week that you first feel fetal movement. Most women first experience this some time between 18 and 20 weeks, although there can be a large amount of variation. Many women report feeling fetal movement earlier with their second and/or subsequent pregnancies. Many women describe the sensation of early fetal movement as a ‘fluttering’ – or bubbles.
If you are suffering from pregnancy-related back pain, improving your posture could help. Yoga is a good way to improve posture, but you should make sure that your yoga teacher knows that you are pregnant, as some yoga poses are not recommended during pregnancy. You may also be experiencing tingling and/or numbness in your fingers and/or toes. This is a common pregnancy symptom and is probably due to swelling tissue pressing on nerves. It is usually nothing to worry about, but you should talk to your midwife or Doctor if you are concerned about it.
You may also be continuing to suffer with occasional faintness and/or dizziness. This is likely to be caused by restricted blood flow to your brain due to compression of blood vessels by your uterus. If you start to feel dizzy, light-headed or faint, you should act immediately and sit, or lie down as soon as possible. Although occasional dizziness is normal for many women during pregnancy, you should approach your midwife or doctor if you are concerned.
Symptoms to watch out for
Vaginal bleeding is not normal at this stage. Some abdominal pain and backache is normal. Vaginal discharge should be of consistent milky colour and volume. If it is pink or more voluminous you should see a medical professional. This is particularly true if you have had a previous late miscarriage, operation on your cervix or short cervix. It is also important if you are carrying twins.
What is routinely offered on NHS
The midwife will be able to provide you with advice. NHS hospitals may offer you the routine second scan at 18 weeks but it is better to defer it until 22 weeks when the view of the detailed structure is much better. This is called the anomaly scan.
What other care is available
General midwifery and medical advice is available in private clinics for which you do not require a referral letter. An ultrasound scan at this stage can check the baby for abnormalities and assess it's size. It can also determine the sex of the baby quite accurately. If you are concerned about your cervix becoming short or have other concerns about your cervix then an ultrasound scan of your cervix can be reassuring. This gives a better assessment when performed through the vagina.
If you are struggling with back pain a pregnancy safe massage may help.