30 weeks pregnant: fetal development

Your baby now measures a little more than 39.9cm (15.7in) from head (crown) to heel (Hill 2020a), which is similar to the size of a cabbage.

Your baby’s growth, in terms of length, will soon slow down, but they'll continue to gain weight until birth (Hill 2020a). They weigh about 1.3kg (2.9lb) at this stage (Hill 2020a).

White, greasy, moisturizing vernix coats your baby's skin from head to toe and from back to front (Singh and Archana 2008, Taïeb 2018). Vernix helps to protect their skin from its long immersion in amniotic fluid.

Vernix is also antimicrobial, keeping bacterial and fungal infections at bay (Taïeb 2018, Visscher et al 2015). Your baby's immune system is also busy developing, to help protect them against infections (Hill 2020b).

If you shine a torch or a bright light at your bump, you may soon feel your baby respond by turning their head. However, their eyesight is still developing, so try again in a couple of weeks if they don't respond now (Moore et al 2019a).

Your baby's eyesight will continue to develop after birth. When they're born, they'll only be able to see faces and objects within 20cm to 30cm (NHS 2018, von Hofsten et al 2014).

The amniotic fluid surrounding your baby has been increasing every week, but this growth has been slowing as your baby gets bigger. By 37 weeks, the volume of the amniotic fluid will peak at between 700ml and 1,000ml (Carter 2017, Hill 2016c, Moore et al 2019b). This will tail off by the time you reach your due date, when the fluid levels will drop to about 600ml (Hill 2020c).

Check out our pregnancy guide to see what changes could be happening to you at 30 weeks pregnant.