"在授乳期中的" can be translated as "in the lactation period" or "during the breastfeeding/nursing period".
Here are some example sentences for context:
1、 She is in the lactation period and needs extra nutrition.
(她在授乳期中,需要额外的营养。)
2、 During the breastfeeding period, it's important for mothers to maintain a healthy diet.
(在授乳期中,母亲保持健康的饮食很重要。)