In general the risk of pregnancy loss increases when maternal age approaches her late 30s and beyond. Without knowing the details of your circumstances, general advice would be to maintain an normal BMI as maternal obesity or being significantly underweight is associated with obstetric complications. Also avoid excessive alcohol consumption and exposure to cigarette smoke.
For the male partner, watch issues like smoking, alcohol consumption , exercise habits and body weight as these can affect sperm quality.
You have not mentioned whether there was any histological or chromosomal analysis of the pregnancy tissue at the time of miscarriage. If done, it could possibly give a reason for the miscarriage eg trophoblastic change/molar pregnancy, or a chromosomal disorder. Most chromosomal abnormalities in the conceptus are sporadic and not recurrent.
Please do have a pelvic ultrasound to check for any problems that may have arisen since your last pregnancy which could impact on uterine anatomy eg. endometrial polyps or fibroids.
I would suggest screening for thromobophilia in particular antiphospholipid syndrome if you have not already done so, as low molecular weight heparin and aspirin supplementation started at date of a positive pregnancy test does improve birth outcomes.
I would also recommend screening for subclinical hypothyroidism and presence of thyroid autoantibodies as again supplemetation with levo-thyroxine in these circumstances might improve birth outcomes.
I suggest vitamin D supplementation due to the significant prevalence of Vit D deficiency in women with recurrent pregnancy loss.
The use of progesterone is often used in first trimester to prevent miscarrige but the evidence is mixed. The best data is for the use of oral dydrogesterone (Duphaston). There is no strong data for use of progesterone supplementation for luteal phase deficiency for prevention of miscarriage.
There is no clear evidence for the use of immunotherapy, intravenous immunoglobulin or glucocorticoids in recurrent pregnancy loss.
A significant proportion of cases of recurrent pregnancy loss remain unexplained despite detailed investigation. Do not give up! Please be reassured that the prognosis for a successful future pregnancy with supportive care alone is in the region of 75%.
