If you have a very close and trusting relationship with your employer and it feels good to announce your pregnancy before the 13th week of pregnancy, then you should do so. Because especially in the first few weeks, the tiredness and, in frequent cases, the nausea associated with the hormonal change is very great, so that you can no longer perform your full work and it is often easier to play with open cards.
If you work in a profession that involves physically difficult or dangerous work, it is also advisable to inform your employer as soon as possible. As an employer, he is obliged to fulfill his protection obligations under the Maternity Protection Act , which he can only fulfill if he knows it.
If you do not have any limitations (physical or mental) and your work does not pose a danger to you or your unborn child, it is advisable to inform the employer in the 12th week of pregnancy. Because you will then have survived the critical time when miscarriages are statistically the most common.