Some unlucky women experience the onset of morning sickness earlier, at around 4 weeks, but on average women will start to experience the symptoms of morning sickness at week 6.

Newborn babies have not had the chance to develop an advanced immune system yet. Germs from the air, such as the ones that are expelled from sneezing or coughing, direct contact, such as germs on someone’s hands, or contaminated surfaces, like public changing tables, may all be potentially dangerous to newborns.

As well as increasing your risk of having an ectopic pregnancy.

Causes of implantation failure include  genetic defects, thin endometrium, embryonic defects and endometriosis.

Hypothalamic amenorrhea occurs when the hypothalamus, a gland in the brain that regulates body processes, slows or stops releasing gonadotropin-releasing hormone (GnRH), the hormone that starts the menstrual cycle.

Smoking increases your risk of serious heart and blood vessel problems from combination hormonal contraceptives (CHCs) including heart attack, blood clots, or stroke which can be fatal. This risk increases with age and the number of cigarettes smoked.