My wife is 5 months pregnant. She is complaining of a throbbing headache having intensity and style of those she had during paratyphoid which she was diagnosed with about 5 months before conceiving. At that time she was treated with ofloxin for 10 days. Now, since two consecutive days ahe is having these headaches only in the nights. The first night she had a crocin after which she felt better the next morning, the headache came back that night with back pain. What could it be ?