This type of fever is not the only reason women did, and still do, die in childbirth. The reasons are many, and the risks were and still are real.

From The Gentleman's Daughter: Woman's Lives in Georgian England, by Amanda Vickery:

"Even by the revised figures, perinatal complication was probably the single most common cause of death in women aged twenty-five to thirty-four, accounting for one in five of all deaths in this age group. ...in a large village a moman might see a conteporary die in childbed every third year." (p. 98)