18 weeks pregnant: what is happening this week

14.2 cm this week, roughly a bell pepper, with hearing, swallowing and sucking reflexes all developing together and significant movement of the arms and legs. The anomaly scan window opens now: the NHS offers it between 18 and 21 weeks, and it is a different animal from the dating scan. It takes longer, it is detailed, and it is looking specifically at how the body has formed - the heart, the spine, the brain, the kidneys, the limbs, the placenta. That is worth stating plainly rather than glossing, because a scan described only as the one where you find out the sex sets people up badly for what the appointment actually is. The sex is incidental and in many trusts you have to ask. Most anomaly scans find nothing of concern. Some find something that changes what happens next, and the reason the scan exists is that finding it before birth allows planning that cannot happen afterwards. Going in knowing what the sonographer is looking for makes the silence while they measure much easier to sit through.