The ovulation period is one of the important periods for women to become pregnant, and endometrial thickness is one of the factors that affects pregnancy. Generally speaking, during ovulation, the thickness of the endometrium should be between 1.0-1.4mm. If the thickness of the endometrium is only 7mm, it may affect pregnancy.

However, this is not absolutely the case. Some women may have an endometrial thickness of 7mm during ovulation and still be able to get pregnant. However, this is very rare and needs to be done under the guidance of a professional doctor.

If a woman's endometrium is only 7mm thick, she may need treatment under the guidance of a professional doctor to help increase her chances of pregnancy. Treatment may include medications or surgery.

To sum up, if a woman's endometrium is only 7mm thick, it may be difficult to get pregnant. However, this is not an absolute situation and requires treatment under the guidance of a professional doctor.