The sixteenth week of pregnancy marks the start of a 3-week growth spurt. The fetus currently measures between 10.9cm and 11.9cm (crown to rump) and weighs around 78g, however this weight is likely to double during the coming 3 weeks.
By this stage, the fetus is inhaling and exhaling amniotic fluid through the lungs, and both the circulatory system and urinary tract are fully functioning. Muscles are continuing to develop and grow stronger. In particular, the muscles in the back and around and spine have gained strength and the fetus is now able to stretch and straighten more.
The fetus is able to hear external sounds, such as music or other peoples’ voices. In addition to this, both the eyebrows and eyelashes are now fully developed. The eyes, although still beneath closed eyelids, are now capable of making small side-to-side movement and are even able to perceive light.
Lanugo – the downy hair that has been sprouting to cover the fetus’ delicate skin – now covers the entire body and serves the double purpose of protecting the delicate, paper-thin skin and also helping to maintain a constant body temperature (half a degree warmer than your own body temperature). This fine hair is usually completely shed before birth.
You may now be able to feel the first flutters of movement from the fetus. However, many women do not experience this until later in their pregnancy.
In line with the growth spurt of the fetus, you are also likely to be gaining weight. You should aim for slow and steady weight gain and try and eat healthily – maximising nutritious foods and minimising ‘junk’ foods. You may also be finding that your breasts are continuing to grow. You may find it helpful to buy a more supportive bra and go for a fitting to ensure that you are wearing the correct size.
You may experience a ‘twinge’ of pain in your sides if you move suddenly. This pain is due to the ligaments on either side of your uterus and pelvis stretching to accommodate your expanding uterus. These pains are normal, but if they continue for a period of days, or become more severe, you should seek the advice of your midwife. You may also be suffering from lower back pain. This is caused by your new posture as you lean backwards to compensate for your growing bump It may help your aching muscles to take a warm bath.
Many women also find prenatal massage beneficial. You should always seek advice from your midwife before using essential oils during massage.
Symptoms to watch out for
Any vaginal bleeding or significant abdominal pain is not normal at this time. The tummy is starting to get noticeably bigger. Pain is probably due to stretching of the ligaments however there are sometimes more significant causes such as urinary tract infection or fibroids. There may be some normal vaginal discharge but this should be constant in colour and quantity. Many women have pregnancy related headaches which usually improve with time but should be checked if they don’t settle with paracetamol.The stretching and stressing of bones, ligaments and muscles often leads to pains particularly in the spine and pelvis.
What is routinely offered on NHS
By now you should have had contact with your local GP or midwife. They will be able to give you general advice and your pregnancy blood testing should have been done. If they find you have a significant issue they may refer you to the local hospital's ultrasound department. An ultrasound scan should be reassuring particularly if you are experiencing vaginal bleeding. If you have specific risk issues you will be referred to a consultant specialist.
What other care is available
If you choose to do so you can self refer yourself to a private clinic. There is no need for a referral letter. In a private clinic you can see a doctor or a midwife. An ultrasound scan is available at short notice to provide reassurance as are other investigations. A consultant specialist will be available to assess and advise you about particular concerns.
You can access a sexing scan from this week onwards to reveal your baby's gender, our sexing scans include a short preview 4D ultrasound video on your phone.