15 Weeks

You are now 15 weeks pregnant (or in your 16th week if that's how you prefer to count it).

Your baby is still small enough to fit into the palm of your hand. New this week - light sensitivity and a bad case of the hiccups, a precursor to breathing. You can't hear them because her system is filled with fluid rather than air but don't be surprised if you feel them later on.

Although you've probably gained between 2.2kg and 4.5kg, your baby weighs in at only about 70g. He measures nearly 9.1cm long, crown to rump. Legs are growing longer than arms now and all his joints and limbs can move. You may be able to find out the sex of your baby by ultrasound now, since the external genitals may be developed enough that the ultrasound technician can tell you if you're going to have a boy or a girl.

One of the most exciting moments of pregnancy is feeling the baby move. Most women notice "quickening", as it's called, between 16 and 20 weeks. You may feel these first wiggles as a flutter low down in your tummy. Once you realise it's actually the baby turning somersaults, make a note to tell your midwife at your next visit. Some women feel the baby move later or less often than others so there's no need to worry if you haven't noticed your baby moving yet.

Around now you'll be offered an antenatal test to screen for birth defects. The multiple marker screening test, which measures levels of alpha-fetoprotein (AFP) among other things, is usually performed between 15 and 20 weeks. Ask your midwife which marker test you will be offered as some are more limited than others. Amniocentesis isn't routine, but it's often recommended for women over 35 and those with a history of birth defects. It's usually carried out at around 15 to 20 weeks. Genetic counsellors, on hand when you have the procedure, can explain the full implications of these tests for chromosomal abnormalities.

Your immune system is slightly impaired when you’re pregnant so you may have noticed that you’ve had more coughs and colds than you normally would. Although, they are annoying and tiring, these sniffles won’t harm your baby. Other infections that you may come across while you are pregnant such as slapped cheek disease, chicken pox or rubella can cause problems for your unborn baby depending on the stage of pregnancy when you catch it – but chances are you’ve already had these infections in your own childhood or, in the case of German measles, been inoculated against it, so you will be immune anyway. Shingles won't harm your baby but you should avoid other pregnant women.