Lab cushions bath

Is this normal? Nipple stimulation causing cramping in early pregnancy? - cramping in early pregnancy more condition_symptoms

I Am 4 weeks pregnant and last night, where they sex with my husband and my nipples massage (sorry) I have menstrual cramps. I never had cramps during the stimulation of the nipple before pregnancy. Is this normal? Damage is the baby? I've heard that nipple stimulation can in late pregnancy to induce labor. You can encourage your nipples during sexual intercourse in early pregnancy cause miscarriage?