Age is definitely a factor. Pitta and vata aggravation can lead to reduced fertility. The one herb which is specific for women's health and for improving fertility is Shatavari (which literally means "1000 spouses"). It is demucent, soothing and calming in nature. Best had as a boiled decoction in warm milk twice a day. Also, do a daily ayurvedic full-body massage with medicated sesame oil before a shower. Chant the Shiva shadakshara mantra (Om Namah Shivaya), especially every Monday. An Ayurvedic consult might reveal any underlying imbalances in your Prakriti.

Best of luck.

I have posted this in another thread, increasing Ojas and Shukra/Artava is the key to fertility (vajikarana) in Ayurveda. Eat ghee on rice and cook with it in general, drink warm milk with raw sugar or honey, blend it or cook it with Shatavari, and Vidhari (wild yam). Also you can soak over night and peel in the morning ten almonds, add a pinch of cardamom, saffron, and a tsp of raw sugar and blend with hot milk. Practice Yoga Assanas especially ones that bend at the waist and abdomen, like yoga Mudra, Durga Pranam, and Cobra. Loosely fill a jar with dates (w/o pits) than fill it with warm ghee so that it takes up the rest of the air space. Mix in ½ tsp of nutmeg and cardamom, add a nice pinch of Saffron, let it sit for a week, than eat one ghee soaked date per day, it can be eaten with soaked & peeled almonds or warm milk, or alone, it’s a nice rejuvenative for any after sex munchies or cravings. Cook with wild yam in soups.
For him: Eat plenty of Urud dhal, soak them and make them into idly or Dosa, Urud dhal roasted in ghee and than cooked with milk and raw sugar is great if you can make it palatable. Make the above Almond milk shake but add, ¼ teaspoon of each: Ashwaganda, Bala, Gokshura, Vidhari, Shatavri, Kapi Kachu, Shimula, Maca, Suma, American Ginseng, ( I call this the “Super Man” formula) Its better to mix these herbs ahead of time and just add a tablespoon as needed. Eat plenty of sweet potatoes and pumpkin. Dates and figs are also good food for this. Massage the body with warm sesame oil a couple times per week, before a warm shower.