11 weeks pregnant: what is happening this week

Four centimetres and a bit, fig-sized, with fingers and toes now separated and tiny fingernails forming on the ends of them. The ears are recognisable in miniature. Behind the scenes the placenta is taking over the work of nourishment from the yolk sac, which is a handover that gets no attention and matters enormously. Circulating blood volume can be up by as much as half by now, and that has consequences you can feel: heat, sweating, and the occasional wave of dizziness that arrives without warning when you stand up too fast. Stomach pains from stretching muscle and ligament are common in the same period. This is the week screening usually gets booked into the calendar. Combined screening for Down's, Edwards' and Patau's syndromes is offered between about 10 and 14 weeks, blood tests for infectious diseases are part of the same package, and the dating scan often does double duty. Three things happen at one appointment, and knowing which is which beforehand is the difference between a scan you understand and a scan you spend afterwards trying to reconstruct.